DETAILED ACTION
Response to Amendment
In the amendment dated 2/13/26, the following has occurred: no amendment has been made.
Claims 1-10 are pending. This communication is a Final Rejection in response to the "Amendment" and "Remarks" filed on 2/13/26.
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 § 102
Claims 9-10 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US 2019/0036105 A1 (hereinafter “US’105”).
As to Claim 9:
Although Claim 9 depends on a method claim, it is directed to the product itself (“a negative electrode”) and therefore is interpreted as a product-by-process claim. Under MPEP §2113, the patentability of a product-by-process claim is determined based on the structure and properties of the resulting product, not on the method by which it is made. Accordingly, anticipation is established if the reference discloses or inherently produces a negative electrode structurally identical to that resulting from the claimed method, even if the reference does not recite the identical process steps (e.g., drying rate formulas).
US’105 discloses ([0012]–[0017], [0049]–[0056], [0062], [0083]–[0085]) a negative electrode for a lithium secondary battery comprising:
a current collector (copper foil) ([0083]);
a first electrode active-material layer and a second electrode active-material layer formed thereon ([0012]–[0017], [0052]);
the first layer containing a higher binder content (2–10 wt%) than the second layer (1–9 wt%) ([0049]);
each layer formed by coating a slurry containing active material, binder, and solvent, and drying to remove the solvent ([0052], [0056]);
a thickness ratio between the two active-material layers of approximately 1:9–5:5 ([0050]); and
enhanced interfacial adhesion strength between the two active-material layers compared to that between the current collector and the lower layer ([0017], [0068]; Table 1).
US’105 further teaches that the final electrode exhibits uniform binder distribution, reduced surface resistance, and improved adhesion ([0021], [0049], [0093]–[0094]), which are the same structural and performance characteristics inherent in the product resulting from the method of Claim 1.
Because the final electrode structure of US’105 is identical to that inherently resulting from the method steps recited in Claim 1, the claimed product is not patentably distinct from that disclosed in US’105. The reference’s explicit disclosure of the same multilayer electrode composition, layer arrangement, and adhesion relationship satisfies all structural limitations of Claim 9.
As to Claim 10:
US’105 discloses a lithium secondary battery including a negative electrode formed by sequentially or simultaneously coating a first slurry and a second slurry on a current collector and drying the coatings to form a multilayer active-material layer ([0012]–[0017], [0052]–[0056], [0083]–[0085]).
US’105 further teaches that the above electrode is incorporated into a lithium secondary battery ([0027]), which includes a positive electrode, separator, and electrolyte together with the multilayer negative electrode.
Claim Rejections - 35 USC § 103
Claims 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over US 2019/0036105 A1 (hereinafter “US’105”) in view of CN 110335989 A (hereinafter “CN’989”).
As to Claim 1:
US’105 discloses a method for manufacturing a negative electrode comprising:
preparing a first slurry and a second slurry each containing an active material, a binder, and a dispersion medium ([0012]–[0017]);
coating the first slurry (lower layer) on a current collector and coating the second slurry (upper layer) on the first slurry sequentially or simultaneously ([0052]–[0056]);
drying both layers under controlled temperature and humidity conditions to form a multilayer active-material layer ([0056]–[0059]);
the binder content of the lower layer is higher than that of the upper layer (2–10 wt % vs 1–9 wt %) and that the drying rate of the coating is controlled between 0.1 – 30 mg s⁻¹ (≈ 0.00024–0.072 g cm⁻² min⁻¹) to suppress binder migration and improve adhesion ([0013], [0050]). However, US’105 does not teach explicitly mathematical relationship defining A = B / (drying rate) and the specific quantitative range of A = 103–300.
In the same field of endeavor, CN’989 also pertains to lithium-ion battery electrode fabrication and specifically describes a coating-and-drying process for an electrode sheet. CN’989 discloses that the binder distribution within an electrode coating is a function of the drying rate and provides a mathematical model (Pe = γH₀/D) correlating binder concentration uniformity with the drying flux (γ) ([0041]–[0043], Figs. 2–3). CN’989 thus explicitly teaches the functional dependence of binder ratio on drying rate and instructs that reducing γ (drying rate) improves binder uniformity and adhesion—thereby optimizing electrode quality.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the process of US’105 in view of CN’989 by expressing and optimizing the known relationship between binder content (B) and drying rate as a quantitative expression such as A = B / (drying rate), and by selecting drying-rate and binder-ratio values that yield an A value within the claimed range (103–300). CN’989 provides the scientific rationale and empirical guidance that binder distribution is inversely proportional to drying rate, and US’105 already discloses overlapping binder ratios (B = 1.1–3.5) and drying-rate magnitudes (0.00024–0.072 g cm⁻² min⁻¹) producing A values that inherently fall within the claimed range. Therefore, combining CN’989’s teaching of the quantitative relationship with US’105’s multilayer-coating process would have been a routine optimization to achieve predictable results—namely, improved binder uniformity and inter-layer adhesion.
As to Claim 2:
US’105 further teaches that the binder ratio (B) between the lower and upper layers is 1.1–3.5 (2–10 wt% vs 1–9 wt%) and that the drying rate is between 0.1–30 mg s⁻¹ (≈0.00024–0.072 g cm⁻²·min⁻¹) ([0013]). These disclosed values inherently yield an A = B/(drying rate) within approximately 15–300, overlapping the claimed A = 103–295 range. Thus, US’105 provides all elements of the claimed method except for the explicit numerical expression of A and the narrowed sub-range of 103–295.
As to Claim 3:
US’105 further teaches that the binder content in the lower layer is 2–10 wt%, and in the upper layer is 1–9 wt% ([0049]), yielding a binder ratio (B) between approximately 0.22–10.0.
However, US’105 does not expressly limit the binder ratio to 1.1–3.4.
With respect to the binder ratio, CN’989 mathematically models binder concentration (C) as a function of drying flux (γ) and shows that binder uniformity is optimized when the binder content ratio between layers is controlled in proportion to the drying rate ([0041]–[0043], Figs. 2–3). The reference therefore provides a clear teaching and motivation to adjust the binder ratio between layers to achieve uniform adhesion and avoid delamination.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to optimize the binder ratio B in the multilayer coating process of US’105 in light of CN’989’s teaching that binder uniformity depends sensitively on the binder-content ratio. Adjusting the known overlapping range of 0.22–10.0 in US’105 to the narrower 1.1–3.4 subrange would have been a routine optimization of a result-effective variable, yielding predictable improvements in adhesion and uniform binder distribution as taught by CN’989. The claimed range falls squarely within the disclosed broader range of US’105 and achieves the same purpose.
As to Claim 4:
US’105 discloses a method for manufacturing a negative electrode comprising preparing a first electrode slurry (lower layer) and a second electrode slurry (upper layer), coating them on a current collector, and drying the coatings at different drying rates ([0012]–[0017], [0050]–[0052]). US’105 explicitly teaches that the thickness ratio between the first and second electrode active material layers is 1:9–3:7 or 1:7–1:5 ([0050]). These ranges correspond to an upper:lower ratio of about 1:9–1:1.4, which substantially overlaps the claimed 1:1.04–1:9 range.
However, US’105 does not disclose the precise lower limit (1:1.04) and the explicit expression of the ratio as an upper:lower relationship rather than lower:upper.
CN’989 describes a coating and drying method for achieving uniform binder distribution, modeling the thickness of the electrode coating (H₀) and the drying rate (γ) as key process parameters (Pe = γH₀/D) influencing binder uniformity and adhesion ([0041]–[0043]). CN’989 thus provides a clear technical motivation to adjust the thickness ratio between layers in conjunction with drying rate to control adhesive migration and improve electrode adhesion.
It would have been obvious to a person skilled in the art before the effective filing date, in view of CN’989’s teaching that coating thickness interacts with drying rate to determine binder distribution uniformity, to optimize the layer-thickness ratio of US’105’s two-layer electrode within the claimed range 1:1.04–1:9. Such adjustment represents a routine optimization of a result-effective variable within an overlapping and predictable range, yielding the same expected improvements in adhesion and binder uniformity described by both references.
As to Claim 5:
US’105 further teaches that the negative electrode active materials may include graphite-based carbon, lithium metal, and lithium titanium oxide (LTO), among other carbonaceous materials and metal oxides ([0039]). Accordingly, US’105 discloses each of the active materials recited in Claim 5, including artificial/natural graphite, hard carbon, soft carbon, Si, SiOx, and LTO.
As to Claim 6:
US’105 discloses a method for manufacturing a negative electrode comprising coating a first slurry on one surface of a current collector and subsequently coating a second slurry on the first layer to form a multilayer electrode ([0052]–[0056]). US’105 teaches that the process may be performed sequentially or continuously, using a multi-stage coating and drying apparatus wherein each layer is deposited in close succession without significant delay between steps ([0056]).
However, US’105 does not teach the specific time interval of 0.6 seconds or less between the coating of the lower and upper layers.
CN’989 discloses a coating and drying process that optimizes binder uniformity and adhesion by controlling drying parameters and coating timing. CN’989 teaches that binder migration is minimized when drying begins immediately after slurry coating, emphasizing the advantage of continuous or near-simultaneous coating operations to maintain a uniform binder concentration ([0003], [0043]).
It would have been obvious to a person skilled in the art before the effective filing date, in view of CN’989, to perform the sequential coating of US’105 with a shortened or near-simultaneous interval between coating the first and second slurries in order to minimize binder segregation and improve interlayer adhesion. Reducing the coating interval to sub-second timescales (e.g., ≤ 0.6 s) would have been a predictable optimization of a known result-effective variable (coating timing) in continuous multilayer coating processes, yielding improved binder uniformity and adhesion as expressly taught by CN’989.
As to Claim 7:
US’105 further teaches that the binder polymer may be selected from polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyacrylic acid, polyvinyl alcohol, carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and various combinations thereof ([0041]).
As to Claim 8:
US’105 discloses a method for manufacturing a negative electrode comprising preparing a first slurry and a second slurry containing active materials, binders, and solvents, coating each slurry on a current collector, and drying to form a multilayer electrode ([0012]–[0017], [0052]–[0056]). US’105 further teaches that the binder used in the slurries may include styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) ([0049]), and that these binders can be used independently or in combination in both layers of the multilayer electrode.
As to Claim 9:
US’105 discloses ([0012]–[0017], [0049]–[0056], [0062], [0083]–[0085]) a negative electrode for a lithium secondary battery comprising a current collector (copper foil) ([0083]) and a first electrode active-material layer and a second electrode active-material layer formed thereon using the process of Claim 1 above ([0012]–[0017], [0052]).
As to Claim 10:
US’105 discloses a lithium secondary battery including a negative electrode formed by sequentially or simultaneously coating a first slurry and a second slurry on a current collector and drying the coatings to form a multilayer active-material layer using the process of Claim 1 above ([0012]–[0017], [0027], [0052]–[0056], [0083]–[0085]).
Response to Arguments
Applicant's arguments filed 2/13/26 have been fully considered but they are not persuasive.
Applicant argues that the rejection of claims 9–10 as anticipated by US 2019/0036105 A1 (“US’105”) is improper because claim 9 recites process features including parameters A and B, which allegedly confer distinctive properties to the negative electrode, as evidenced by data in Table 3 of the specification. Applicant further asserts that the process steps recited in claim 9 should therefore be considered in determining patentability. This argument is not persuasive.
Claim 9 recites:
“A negative electrode obtained from the method for manufacturing a negative electrode as defined in claim 1.”
Thus claim 9 is a product-by-process claim. As set forth in MPEP §2113 and In re Thorpe, 777 F.2d 695 (Fed. Cir. 1985), the patentability of a product-by-process claim is determined based on the structure and properties of the product itself, not on the process by which the product is made.
Accordingly, the process limitations recited in claim 1 do not impart patentable weight unless they result in a structurally distinct product.
US’105 discloses a negative electrode comprising:
a current collector (e.g., copper foil),
a first electrode active material layer and a second electrode active material layer formed thereon, and
binder distribution within the electrode layers that improves adhesion and electrical performance.
These features correspond to the same structural configuration that results from the process recited in claim 1.
Applicant’s argument relies primarily on experimental data allegedly showing improved resistance values for electrodes produced under certain conditions within the claimed ranges. However, improved performance alone does not establish structural distinction between the claimed product and the product disclosed in the prior art. See In re Best, 562 F.2d 1252 (CCPA 1977).
Moreover, the data presented in Table 3 merely compares the applicant’s own examples with a comparative example in the specification. Such evidence does not demonstrate that the electrode produced according to US’105 would necessarily lack the same properties or structure.
Because applicant has not demonstrated that the claimed negative electrode possesses a structure that is distinct from the electrode disclosed in US’105, the product defined in claim 9 is not patentably distinct from that disclosed in US’105.
Accordingly, the rejection of claims 9–10 under 35 U.S.C. §102 is maintained.
Applicant argues that the combination of US’105 and CN 110335989 A (“CN’989”) fails to render the claims obvious because neither reference discloses the relationship A = B / (drying rate) or the specific range A = 103–300, and because the claimed ranges allegedly produce unexpectedly superior resistance characteristics. These arguments are not persuasive.
Applicant argues that the applied references do not explicitly disclose the parameter A = B/(drying rate).
However, obviousness does not require that the prior art disclose the exact mathematical expression recited in the claims. The proper inquiry is whether the prior art teaches the underlying variables and their functional relationship.
US’105 teaches a multilayer electrode structure in which the binder content differs between layers, thereby establishing a binder concentration ratio between the layers.
CN’989 teaches that binder distribution within an electrode coating is governed by the drying rate during solvent evaporation, and provides a mathematical model correlating binder distribution with drying rate (e.g., through the Peclet number relationship). Thus CN’989 explicitly recognizes drying rate as a key parameter controlling binder migration and distribution.
Because the prior art teaches that binder concentration and drying rate jointly influence binder distribution within the electrode coating, a person of ordinary skill in the art would have recognized these variables as interacting parameters affecting the same phenomenon.
Expressing the interaction between these known variables in the form of a derived parameter such as A = B / (drying rate) represents no more than a mathematical characterization of known relationships, which does not render the subject matter nonobvious.
Both references identify binder content and drying rate as variables that affect binder distribution and electrode performance.
Where the prior art recognizes that a variable affects a particular result, discovering an optimum or workable range for that variable is considered routine optimization within the skill of the ordinary artisan. See In re Aller, 220 F.2d 454 (CCPA 1955) and In re Peterson, 315 F.3d 1325 (Fed. Cir. 2003).
Because:
US’105 teaches controlling binder content between layers, and
CN’989 teaches controlling drying rate to regulate binder distribution,
it would have been obvious to optimize the relationship between these variables to achieve improved binder distribution and adhesion within the multilayer electrode structure.
Selecting drying rate and binder ratio values that produce a parameter value within the claimed range A = 103–300 would therefore have been a matter of routine experimentation.
Applicant asserts that Examples 3, 9, and 14 demonstrate unexpectedly superior resistance values compared to Comparative Example 1.
This evidence is not persuasive for several reasons.
First, evidence of unexpected results must be compared with the closest prior art. The data provided in the specification compares only examples within the application to an internal comparative example rather than to the electrode structures disclosed in the applied references. Consequently, the data does not establish that the claimed invention performs unexpectedly relative to the prior art.
Second, the comparative example falls outside the claimed ranges. Comparative Example 1 has values of B = 1 and A = 95, both of which lie outside the claimed ranges. Showing improved results relative to a value outside the claimed range does not establish that the claimed range itself is critical or produces unexpected results.
Third, the claims encompass a broad range of values for parameters A and B. The limited number of examples presented in the specification does not establish that the alleged improvement is commensurate in scope with the claims.
For these reasons, applicant's arguments filed 2/13/26 have been fully considered but they are not persuasive.
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.
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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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tong Guo can be reached at (571) 272-3066. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JIMMY VO/
Primary Examiner
Art Unit 1723
/JIMMY VO/ Primary Examiner, Art Unit 1723