Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of Claims
Applicant’s arguments filed 05/15/2026 have been fully considered. No amendment has been presented. Claims 1, 3-10 are pending review in this Office action.
Upon considering said arguments, the previous rejections under 35 U.S.C. 103 set forth in the Office action mailed 05/30/2025 has/have been maintained for the reasons discussed hereinbelow.
Response to Arguments
Applicant cites the following elements (Remarks filed 05/15/2026; pp. 4-5) of the present invention, reproduced below:
Element 1: A first mixture comprising an electrode active material and a thickener solution;
Element 2: A step of kneading the first mixture;
Element 3: A step of preparing a second mixture comprising the kneaded first mixture and a conductive agent;
Element 4: The solid content of the second mixture is lower than the solid content of the first mixture; and
Element 5: The kneading is performed at a shear force of 100 to 150 Pa.
Specifically, by adding the conductive agent after kneading a mixture containing the active material, the resultant battery’s negative electrode resistance and capacity retention are significantly improved (Remarks p. 5).
Applicant asserts that cited references Sumi et al. (US20130193371A1, “Sumi”) in view of Kim et al. (US20150364749A1, “Kim”) fail to disclose or suggest adding the conductive agent after kneading a mixture containing the active material, i.e., Element 3 (Remarks p. 5). While this argument has been considered, it has not been found persuasive for the reasons discussed below:
Sumi discloses a conventional method in which the active material and conductive agent are mixed simultaneously, thus failing to disclose Element 3 (Sumi [0021]) (Remarks pp. 5-6). While not necessarily limited to this method, Sumi is not relied upon to disclose this feature.
Applicant cites the following excerpt of Kim Example 1 (emphasis by Applicant):
(2) Prepare an Electrode Active Material Dispersion
[0064] 646.7 g of LiCoO2 as a positive electrode active material was dispersed in 140.8 g of NMP as a second dispersion medium to prepare an electrode active material dispersion (a ratio of solids: 82.1%).
(3) Prepare an Electrode Active Material Slurry
[0065] The conductive agent dispersion was slowly added to and dispersed in the electrode active material dispersion to prepare an electrode active material slurry (a ratio of solids: 71.5%). In this instance, the electrode active material slurry was prepared by dispersing at 4,000 rpm for 60 minutes using a dispersion machine being generally used (homogenizer).
As shown in this example, Applicant asserts that Kim’s “electrode active material dispersion and conductive agent dispersion are mixed before using the disperser. That is, Kim neither discloses adding nor suggests adding the conductive agent after kneading a mixture containing an active material as in the present invention”. (Remarks pp. 6; emphasis by Applicant). In this assertion, Applicant appears to correlate Kim Step (3) of dispersing a conductive agent dispersion in an electrode active material dispersion with Applicant’s Comparative Example 1, where the conductive agent is mixed during the preliminary kneading of the electrode active material (Remarks p. 8).
While this argument has been considered, it has not been found persuasive as this interpretation of Kim is not correct. Before adding the conductive agent (i.e. Step (3) in Kim’s examples), Kim teaches a Step (2) of dispersing the active material in a solvent to “prepare an electrode active material dispersion”. Notably, no conductive agent is added during Step (2) ([0064]).
Kim’s Step (2) of “dispersing” the active material into an electrode active material dispersion in fact correlates with Applicant’s step of “kneading” the first mixture; supported by ¶[0031] of the inst. spec., “When the kneading process is performed within the above range, it is possible to uniformly disperse the electrode active material in the first mixture” (emphasis by Examiner). Thus, after Kim’s first mixture (the electrode active material dispersion) is prepared, Kim teaches the Step (3) where “the conductive agent dispersion [is] slowly added to and dispersed in the electrode active material dispersion to prepare an electrode active material slurry (i.e., a second mixture)” ([0065]).
In other words, Kim teaches in Step (3) adding the conductive agent after dispersing (e.g., kneading) a mixture containing an active material as in the present invention as per Applicant’s Element 3.
Further supporting this interpretation is Kim’s Comparative Example 1, where the conductive agent, active material, binder solution, and a solvent are mixed together simultaneously (Kim [0069]), which follows the conventional process highlighted by Applicant in Sumi (Remarks p. 6).
Therefore, an ordinary skilled artisan modifying Sumi’s process according to Kim’s teaching would arrive at the present invention, particularly, the aspects of Element 3 emphasized by Applicant.
Applicant further cites unexpected improvements to battery resistance and capacity retention resulting by adding the conductive agent after kneading the mixture containing the active material (i.e., the procedure of Applicant’s Example 1) compared to conventional processes where the active material and conductive agent are added prior to kneading, that is, kneaded simultaneously (i.e., Applicant’s Comparative Example 1, asserted by Applicant to correlate with Sumi and Kim’s processes).
While this argument has been considered, it has not been found persuasive, as these improvements to battery resistance and capacity retention would be expected by a skilled artisan in view of Kim’s teaching.
As discussed above, Kim teaches a direct improvement by adding a conductive agent after dispersing, e.g. kneading, a first mixture containing an active material in producing a battery electrode (Kim Examples 1, 2, [0061-0068]) compared to mixing the conductive agent and active material simultaneously (Comparative Example 1, [0069]).
This is advantageous to uniformly disperse the conductive agent (Kim [0025-0026] as cited in p. 3 of the Office action filed 02/18/2026), and is experimentally shown to improve the battery capacity ([0074], FIG. 3; Example 2 in dashed line, Comparative Example in solid lines).
Furthermore, the output voltage of the battery is also improved (Kim [0076-0077], FIG. 4). As the same active materials (thus, the same electrical potentials) are present between Kim’s Example and Comparative Example batteries, but the Comparative Example undergoes a drop in voltage output relative to the Example at the same currents (FIG. 4), the resistance inside the Comparative Example must inherently be larger (and thus the conductivity lower) as a property of Ohm’s Law:
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It would also be expected, in light of Kim’s teaching that the conductive agent prepared using the exemplary method has improved efficacy ([0026]), that a resistance of the battery (being inversely proportional to the conductivity) would also be reduced.
Therefore, the cited improvements to battery resistance and capacity retention from adding the conductive agent after kneading the mixture containing the active material are expected in view of Kim’s teaching and are evidence of obviousness (MPEP 716.02 (c)).
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.
Claim(s) 1, 3-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sumi et al. (US20130193371A1 cited in Office action filed 05/30/2025) in view of Kim et al. (US20150364749A1 cited in Office action filed 02/18/2026)
Regarding claim 1, Sumi discloses a method for manufacturing a negative electrode slurry (“paste”) ([0059]), where an example embodiment of the method comprises:
a) kneading a first mixture (“rough kneading”) including a negative electrode active material (“active material”) and a thickener solution (“thickener”, “water as a solvent”) ([0059], [0025]; the thickener dissolves in the solvent during mixing and thus becomes a thickener solution); and
b) preparing a second mixture (“diluted paste”) including the kneaded first mixture (“paste”) wherein a solid content in the second mixture (~54 wt%, [0058]) is smaller than that of the first mixture (63.5 wt%, [0053]) through addition of solvent ([0059]); while Sumi envisions considerations of dispersing the slurry materials ([0007-0008]) including the conductive agent (“conductive additive”, [0021]), Sumi fails to explicitly indicate step b) of preparing the second mixture as further including a conductive agent as claimed.
Kim is directed to a similar method of manufacturing a slurry (Kim, abstract) such as a negative electrode slurry ([0016]) comprising a step a) (“S1”) of forming a first mixture (“electrode active material dispersion”) including a negative electrode active material in a dispersion medium and a step b) (“S2”) of preparing a second mixture including the first mixture and a conductive agent in a dispersion ([0007]), the second mixture inherently comprising a lower solid content than that of the first mixture (60-90 wt%) from being combined with the conductive agent dispersion (5-20 wt%) ([0010]). Compared to conventional methods of mixing both the active material and conductive agent at high viscosity in an initial mixing step, Kim’s method of separately providing the conductive agent in step b) improves slurry stability ([0036]) and improves conductive agent dispersion, inhibiting cycle characteristic degradation even when less conductive agent is preset in the slurry ([0025-0026]).
Similarly, Sumi desires to ensure stable dispersion of the negative electrode slurry components ([0007-0010]). Consequently, in seeking to ensure slurry stability and improve conductive agent dispersion, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to modify Sumi’s step b) to further include a conductive agent dispersion in the second mixture as taught by Kim with a reasonable expectation of success, resulting in a step b) of preparing a second mixture including the kneaded first mixture and a conductive agent wherein a solid content in the second mixture is smaller than that of the first mixture.
Modified Sumi further discloses a need to optimize the torque applied during kneading in step a) (i.e., at the start of kneading); excess torque (T4) causes dilatancy in the slurry ([0041], FIG. 5) where the fluidity is reduced and material dispersion and electrode production is impaired ([0007]), while insufficient torque (T6) reduces the kneading efficiency and requires a longer kneading duration to disperse the slurry ([0042-0043], FIG. 5). While Sumi does not explicitly disclose a shear force of kneading as being 100 Pa to 150 Pa, a skilled artisan would recognize the following relations where kneading force is common to the kneading torque and kneading shear stress:
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where the distance and area components are fixed values dependent on the geometry of the kneading apparatus (i.e., length of stirrers (3) or size of vessel (2) in Sumi FIG. 1) and do not change when adjusting the torque or shear stress. In other words, a skilled artisan optimizing the kneading torque would proportionally optimize the kneading force, and in doing so, would also optimize the kneading shear stress by a proportional amount, such that it would be obvious for a person having ordinary skill in the art seeking the above torque optimization with respect to Sumi’s considerations to simultaneously optimize the kneading shear force. In doing so, a skilled artisan would reasonably utilize at least a portion of the claimed range of 100-150 Pa as at least some amount of shear force is inherently applied during kneading (MPEP 2144.05 II).
Regarding claims 3-4, 6-8 modified Sumi discloses the method of claim 1, wherein an experimental example of the method comprises a solid content of the first mixture (“during rough kneading”) of 63.5 wt% (Sumi [0053]), which falls within the claimed range of 55-70 wt% (claim 3).
Sumi further discloses the method of claim 1 further comprising a step c) of preparing a third mixture (“final paste”) by mixing the second mixture (“diluted paste”) and a binder ([0059]) (claim 7). A solid content of the third mixture is 54 wt% ([0058]), which falls within the claimed range of 35 to 55wt% solids (claim 8).
While Sumi fails to explicitly indicate a solid content in the second mixture (“diluted paste”), the only material difference between Sumi’s second mixture and third mixture (“final paste”) is the addition of 1 wt% binder based on the active material weight ([0050], [0059]); consequently, the second mixture would comprise slightly less than 54 wt% solid content and would fall within the claimed range of 35 to 55wt% solids (claim 4).
Furthermore, while Sumi fails to specify a numerical value of the second mixture viscosity, Sumi’s second mixture having about ~54 wt% solids appears to have a composition falling in the intermediate between that of Applicant’s Example 1 (45.1 wt% solid, 6917 cP viscosity) and Comparative Example 1 (61.7 wt% solids, 14040 cP viscosity) after injection of SWCNT (Instant specification [0063], [0072-0073], pp. 21 Table 1) such that a skilled artisan would expect Sumi’s second mixture’s inherent viscosity to exist within a relatively similar range (i.e, about 6000-14000 cP), being at least within the claimed range of 2000-15000 cP (claim 6)
Regarding claim 5, modified Sumi discloses the method of claim 1. Sumi fails to specify a numerical value of the kneaded first mixture viscosity; however, Sumi’s first mixture (63.5 wt% solids, Sumi [0053]) appears to have a composition falling in the intermediate between that of Applicant’s Comparative Example 1 (61.7 wt% solid, 14040 cP viscosity) and Comparative Example 2 (65 wt% solids, 16230 cP viscosity) after injection of SWCNT (Instant specification [0072-0075], pp. 21 Table 1)
such that a skilled artisan would expect Sumi’s first mixture’s inherent viscosity to exist within a relatively similar range (i.e, about 14000-16000 cP), being at least within the claimed range of 3000-20000 cP.
Regarding claim 9, modified Sumi discloses the method of claim 1. Sumi discloses the selection of at least one conductive agent (“conductive additive”) in the slurry (Sumi [0021]), but fails to specify the conductive agent as being at least one of those selected from the group of claim 9.
Kim, relied on to teach the addition of the conductive agent in the second mixture, further teaches a suitability of selecting carbon nanotube, acetylene black, carbon black, graphite, Ketjen black,
carbon black, carbon fiber, and carbon fiber as conductive agents because these materials do not cause a chemical change in a lithium secondary battery (Kim [0045]); consequently, it would be obvious to select at least one of these options as the conductive agent with a reasonable expectation of success (MPEP 2144.07).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Sumi in view of Kim as applied to claim 9 above, further in view of Predtechenskiy et al. (“SWCNT vs MWCNT and Nanofibers. Applications in Lithium-Ion Batteries and Transparent Conductive Films” cited with copy in Office action filed 12/30/2024).
Regarding claim 10, modified Sumi discloses the method of claim 9; while Kim teaches a suitability of selecting carbon nanotubes as the conductive agent (Kim [0013]), where the genus of carbon nanotubes would be understood to include the species of single-walled carbon nanotube (SWCNT), Kim fails to explicitly specify the inclusion of SWCNT.
Predtechenskiy is directed to the use of carbon nanotubes in various applications including as a conductive agent in lithium-ion batteries (Predtechenskiy, Abstract), and teaches SWCNTs as being particular advantageous conductive agents due to their low internal resistance and greatly improve internal resistance and cell cycling in this role (Predtechenskiy, highlighted segment on page 116).
Consequently, in seeking to reduce internal resistance and improve cell cycling properties of the negative electrode slurry produced by modified Sumi’s method, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to include SWCNT as a conductive agent. Such a modification would be made with a reasonable expectation of success as Kim discloses a general suitability of using carbon nanotubes as the conductive agent, with SWCNTs being a specific type of carbon nanotube.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/E.C./Examiner, Art Unit 1751
/Haroon S. Sheikh/Primary Examiner, Art Unit 1751
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