DETAILED ACTION
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 .
Response to Amendment and Claim Status
The amendment filed 17 July 2025 has been entered. Claim 5 has been canceled. Claims 1, 3, 4, and 6 are pending in the application.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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, 4, and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Kawai et al. (JP 2020/071944 A; see attached machine translation) in view of Harada et al. (JPH 10154513 A; see attached machine translation).
Regarding Claim 1, Kawai discloses a nonaqueous electrolyte secondary battery (see nonaqueous electrolyte lithium-ion secondary battery 100, [0012], FIG. 1) comprising:
an electrode body (see flat-shaped wound electrode body 20, [0012], FIG. 1 and 2) having a positive electrode (see positive electrode sheet 50, [0014], FIG. 1 and 2), a negative electrode (see negative electrode sheet 60, [0014], FIG. 1 and 2), and a separator (see separator sheets 70, [0014], FIG. 1 and 2); and
a nonaqueous electrolyte solution (see electrolyte 80, [0014], FIG. 1), wherein
the negative electrode (60) has a negative electrode active material layer (see negative electrode active material layer 64, [0014], FIG. 1 and 2), wherein the negative electrode active material layer (64) comprises graphite ([0016]) and a binder (see lithium polyacrylate (PAALi), [0016]),
the positive electrode (50) has a positive electrode active material layer (see positive electrode active material layer 54, [0014], FIG. 1 and 2), and
the nonaqueous electrolyte solution (80) contains lithium bis(oxalato)borate ([0018]).
Kawai does not disclose wherein the binder comprises styrene-butadiene rubber (note that while Kawai ([0025]) does reference styrene-butadiene rubber as a binder in comparative examples, these are not representative of the invention of Kawai). Instead, Kawai discloses ([0016]) that the binder comprises lithium polyacrylate (PAALi), and can further comprise other binder components within a range that does not impair the effects of the invention.
Harada teaches a non-aqueous electrolyte battery ([0010]) comprising: an electrode body (see spiral electrode assembly, [0022]) having a positive electrode ([0010]), a negative electrode ([0010]), and a separator ([0022]); and a nonaqueous electrolyte solution (see non-aqueous electrolyte, [0017]), wherein the negative electrode has a negative electrode active material layer ([0019]), wherein the negative electrode active material layer comprises graphite ([0019]) and a binder ([0016]), wherein the binder comprises styrene-butadiene rubber ([0016], [0019]). Harada teaches ([0016]) that using a copolymer having a butadiene group such as styrene-butadiene rubber as the negative electrode binder improves flexibility and binding effect.
Harada and Kawai are analogous to the claimed invention as they are in the same field of nonaqueous batteries capable of cycling lithium. It therefore would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the non-aqueous electrolyte secondary battery of Kawai such that the negative electrode active material layer further comprises styrene-butadiene rubber, as taught by Harada, for the purpose of improving flexibility and binding effect.
Modified Kawai does not explicitly disclose wherein the styrene-butadiene rubber is synthesized using LiOH.
However, it is noted that these limitations are considered to be product-by-process limitations, and even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process (In re Thorpe, 227 USPQ 964,966). Once the Examiner provides a rationale tending to show that the claimed product appears to be the same or similar to that of the prior art, although produced by a different process, the burden shifts to Applicant to come forward with evidence establishing an unobvious difference between the claimed product and the prior art product (In re Marosi, 710 F.2d 798, 802, 218 USPQ 289, 292
(Fed. Cir. 1983), MPEP § 2113).
In the instant case, it is firstly submitted that as styrene-butadiene rubber does not comprise acidic protons in either the styrene- or butadiene-derived repeating units of its structure, one of ordinary skill in the art would not reasonably expect a significant amount of Li, Na, or any other metal cation to be present regardless of the alkali base (e.g. LiOH, NaOH, etc.) used during synthesis. Furthermore, while it is possible that a small amount of residual alkali base could be present in the styrene-butadiene rubber post-synthesis, one of ordinary skill in the art would reasonably expect that efforts would be made to remove it by the manufacturer, as the presence of contaminating strong alkali base in the final product would be detrimental to many of the applications in which styrene-butadiene rubber is used. Based on the above reasoning, the claimed styrene-butadiene rubber appears to be the same or similar to that of modified Kawai, though possibly produced by a different process.
Furthermore, Kawai teaches ([0003]–[0006]) that for nonaqueous electrolyte secondary batteries (100) containing lithium bis(oxalato)borate in the nonaqueous electrolyte solution (80), when Na content remains in the negative electrode (60) in the form of impurities, sodium bis(oxalato)borate is produced near the center of the negative electrode (60), leading to a decrease in the resistance to lithium deposition. Kawai further teaches ([0006]) that the Na content in the negative electrode (60) can be reduced by a washing step or using materials that do not contain Na. Additionally, Harada teaches ([0007], [0011]) that elution of Na ions, K ions, etc. out of the negative electrode and into the electrolyte adversely effect storage and cycle characteristics, while eluted Li ions do not. It is therefore submitted that in the event that the styrene-butadiene rubber of modified Kawai is not determined to be the same or similar to the presently claimed styrene-butadiene rubber synthesized using LiOH, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the non-aqueous electrolyte secondary battery of modified Kawai such that the styrene-butadiene rubber is synthesized using LiOH, as doing so would ensure that the material does not contain Na, and therefore does not adversely affect the resistance to lithium deposition and storage and cycle characteristics of the non-aqueous electrolyte secondary battery, as taught by Kawai and Harada.
Modified Kawai does not explicitly disclose wherein a ratio (%) of the Na content in the negative electrode active material layer relative to the total of Na content in the positive active material layer, Na content in the negative electrode active material layer, and Na content in the separator, is 5% or lower, or wherein a Na content in the negative electrode active material layer, determined by laser ablation ICP mass spectrometry, is 50 µg/g or lower. As set forth above, Kawai does teach ([0003]–[0006]) that for nonaqueous electrolyte secondary batteries (100) containing lithium bis(oxalato)borate in the nonaqueous electrolyte solution (80), when Na content remains in the negative electrode (60) in the form of Na impurities, sodium bis(oxalato)borate is produced near the center of the negative electrode (60), leading to a decrease in the resistance to lithium deposition, and ([0006]) that the Na content in the negative electrode (60) can be reduced by a washing step or by using materials that do not contain Na. One of ordinary skill in the art will understand that the Na content of the negative electrode (60) as a whole, referred to by Kawai, will be analogous to the Na content of the negative electrode active material layer (64), specifically.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05). In the instant case, Na content in the negative electrode active material layer is a variable that achieves the recognized result of determining the resistance to lithium deposition, making Na content in the negative electrode active material layer a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the Na content of the negative electrode active material layer of modified Kawai such that a ratio (%) of the Na content in the negative electrode active material layer relative to the total of Na content in the positive active material layer, Na content in the negative electrode active material layer, and Na content in the separator, is 5% or lower, and such that a Na content in the negative electrode active material layer, determined by laser ablation ICP mass spectrometry, is 50 µg/g or lower via routine experimentation, for the purpose of achieving an increased resistance to lithium deposition.
Regarding Claim 4, modified Kawai discloses the nonaqueous electrolyte secondary battery according to Claim 1, but does not disclose wherein the negative electrode active material layer (64) further contains a thickener, and the thickener is a salt of carboxymethyl cellulose, and at least part of cations of the carboxymethyl cellulose salt are Li ions.
Harada teaches ([0011]) that the negative electrode has a thickener, the thickener is a salt of carboxymethyl cellulose, and at least part of cations of the carboxymethyl cellulose salt are Li ions. Harada further teaches ([0007], [0011]) that utilizing a lithium salt of carboxymethyl cellulose as the thickener for the negative electrode has the result that lithium ions eluted into the electrolyte do not have any adverse effect on the storage characteristics and cycle characteristics, which would occur in the case of elution of Na ions, K ions, etc.
It would therefore have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the non-aqueous electrolyte secondary battery of modified Kawai such that the negative electrode active material layer contains a thickener, the thickener is a salt of carboxymethyl cellulose, and at least part of cations of the carboxymethyl cellulose salt are Li ions, as taught by Harada, for the purpose of attaining the result that lithium ions eluted into the electrolyte do not have any adverse effect on the storage characteristics and cycle characteristics, which would occur in the case of elution of Na ions, K ions, etc.
Regarding Claim 6, modified Kawai discloses the nonaqueous electrolyte secondary battery according to Claim 1. Kawai ([0012]) further discloses wherein the electrode body (20) is a wound electrode body.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Kawai (JP 2020/071944 A; see attached machine translation) in view of Harada et al. (JPH 10154513 A; see attached machine translation) as applied to Claim 1 above, and further in view of Onizuka (US 2016/0294006 A1).
Regarding Claim 3, modified Kawai discloses the nonaqueous electrolyte secondary battery according to Claim 1, but does not explicitly disclose wherein a ratio of a resistance value at a site of highest resistance relative to a resistance value at a site of lowest resistance, upon measurement of a resistance distribution along a short-side direction of a main surface of the negative electrode active material layer, is 1.10 or lower. Kawai does disclose that Na content remaining in the negative electrode (60) in the form of Na impurities will result in sodium bis(oxalato)borate being produced near the center of the negative electrode (60), leading to a decrease in the resistance to lithium deposition (see [0003]–[0006]).
Onizuka teaches an electrode body (see wound electrode unit 50, [0065], FIG. 2) comprising a positive electrode (see sheet-shaped positive electrode 64, [0065], FIG. 2), negative electrode (see sheet-shaped negative electrode 84, [0065], FIG. 2) further comprising a negative electrode active material layer (see negative electrode mixture layer 86, [0066], FIG. 2), and a nonaqueous electrolyte solution to which lithium bis(oxalato)borate has been added ([0067]). Onizuka discloses that a ratio of a resistance value at a site of highest resistance relative to a resistance value at a site of lowest resistance, upon measurement of a resistance distribution along a short-side direction of a main surface of the negative electrode active material layer (86) (i.e. a “short-side resistance ratio”) should be as close to 1.0 as possible, by teaching ([0007], [0014]) that the presence of high amounts of [B(C2O4)2] in the central region of the negative electrode (84) along the width (i.e. short-side) direction as the result of sodium bis(oxalato)borate precipitation leads to a higher electrical resistance in the central region in comparison to the end regions and the precipitation of charge carrier-derived substances such as lithium metal in this central region. In other words, Onizuka implicitly teaches that minimal variation in the electrical resistance along a short-side direction of a main surface of the negative electrode active material (86) would indicate minimal sodium bis(oxalato)borate precipitation and result in suppressed precipitation of charge carrier-derived substances such as lithium metal in the central region of the electrode body (50). Onizuka is analogous to the claimed invention as it is in the same field of nonaqueous electrolyte batteries capable of cycling lithium.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05). In the instant case, the short-side resistance ratio is a variable that achieves the recognized result of determining the level of lithium metal precipitation which occurs in the central region of the electrode body, as taught by Onizuka, making the short-side resistance ratio a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the short-side resistance ratio of modified Kawai to be 1.10 or lower via routine experimentation, for the purpose of suppressing lithium metal precipitation in the central region of the electrode body.
Response to Arguments
Applicant’s arguments in the Remarks filed 17 July 2025 have been fully considered but are not persuasive.
Applicant argues (Remarks p. 4–5) regarding Claim 1 that the claim language “the negative electrode active material layer comprises graphite and a binder, the binder comprises styrene-butadiene rubber synthesized using LiOH”, while a product-by-process limitation, should be given patentable weight because the recited process imparts a structural characteristic to the product, i.e., a lack of NaOH in the final composition. This argument is not persuasive. It is first noted that Claim 1 does not positively recite that the styrene-butadiene rubber lacks NaOH in the final composition, and instead, as described, invokes product-by-process claim language. Secondly, it is submitted that the styrene-butadiene rubber synthesized using LiOH appears to be the same or similar to that of modified Kawai, though possibly produced by a different process, for the reasons set forth in the rejection of Claim 1 above.
Applicant further argues (Remarks p. 4–5) regarding Claim 1 that Kawai fails to teach or suggest a binder comprising styrene-butadiene rubber synthesized using LiOH. While Kawai does not explicitly disclose wherein the binder of the negative electrode active material layer comprises styrene-butadiene rubber, Kawai does disclose ([0016]) that the negative electrode active material layer can comprise other binder components within a range that does not impair the effects of the invention, and Harada teaches ([0016]) the benefits of including styrene-butadiene rubber as a binder in the negative electrode active material layer. Furthermore, both Kawai ([0003]–[0006]) and Harada ([0007], [0011]) teach the benefits of minimizing Na content in electrode components. As such, it is submitted that the combined teachings of Kawai and Harada render obvious the utilization as a negative electrode binder of styrene-butadiene rubber synthesized using LiOH, as set forth in the rejection of Claim 1 above.
Applicant argues (Remarks p. 5) regarding Claim 3 that Onizuka was not applied in a manner sufficient to cure the deficiencies of Kawai, but does not provide any evidence supporting this argument. This argument is therefore not persuasive.
Applicant argues (Remarks p. 5–6) regarding Claim 4 that Harada was not applied in a manner sufficient to cure the deficiencies of Kawai, but does not provide any evidence supporting this argument. This argument is therefore not persuasive.
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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/J.M.F./Examiner, Art Unit 1725
/BASIA A RIDLEY/Supervisory Patent Examiner, Art Unit 1725