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 .
Claims 7 and 10 are objected to because of the following informalities: in claim 7, “a binder” should read --the binder--; in claim 10, “a silicon-based anode active material” should read --the silicon-based anode active material--. Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 4 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 4 recites the polyacrylic acid (PAA) copolymer of claim 3 being a copolymer of PAA and another polymer selected from the claimed group. However, claim 3 does not require the PAA-based binder to include a copolymer of PAA. Thus, it is unclear whether claim 4 further limits the PAA-based binder to require a PAA-based copolymer or is merely placing further limitations on the PAA-based copolymer of claim 3 while still allowing for the PAA-based binder to include only PAA and not a PAA-based copolymer. For the purposes of prosecution, the examiner interprets claim 4 to require the polyacrylic acid-based binder including a polyacrylic acid-based copolymer and the polyacrylic acid-based copolymer is a copolymer of polyacrylic acid and any one of the polymers from the recited list.
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.
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.
Claims 1-5, and 7-11 are rejected under 35 U.S.C. 103 as being unpatentable over Park et al. (US 2025/0349855), hereinafter “Park”, in view of Oshima et al. (US 2024/0021824), hereinafter “Oshima”.
Regarding claims 1 and 11, Park teaches a lithium secondary battery, a cathode, a separator, and an anode (Park, [0001], [0081], [0088]), wherein the anode includes an anode active material layer (corresponding to the claimed anode mixture layer) which may be silicon or a compound containing silicon (corresponding to the claimed silicon-based anode active material) and a copolymer binder (Park, [0062], [0064]-[0065], [0072]) which may include an acrylic acid-based monomer unit (Park, [0047]);
the anode may further include an additional polymer in addition to the copolymer which may be styrene-butadiene rubber (SBR) (Park, [0070]-[0071]).
Park is silent to the Young’s modulus of the SBR.
However, Oshima teaches a polymer for a lithium ion secondary battery electrode binder (Oshima, [0003], [0012]) which may include styrene and butadiene (Oshima, [0048], [0050], [0055]), and a loss modulus (G”) and loss tangent (tan δ) of the polymer (Oshima, [0039], [0042]). The loss tangent may be 0.001 to 0.8 in order to improve pressability allowing the electrode to have excellent close adherence to and a low tendency to peel from the electrode substrate (Oshima, [0040]). The loss modulus is less than 1,000 kPa in order to improve the peel strength of the electrode (Oshima, [0042]).
Thus, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the instant invention to add Oshima’s loss modulus and loss tangent to both the copolymer and SBR components of Park’s binder in order to provide an anode with excellent close adherence to the current collector and improved peel strength (Oshima, [0040], [0042]).
The examiner uses equation (1) below to convert the disclosed loss modulus upper limit to a Young’s modulus (G’) upper limit using 0.8 as the loss tangent value and 1,000 as the loss modulus upper limit value.
G
'
=
G
"
t
a
n
(
δ
)
(1)
Equation (1) gives a Young’s modulus upper limit of 1,250 kPa when the loss tangent is 0.8. The examiner notes that G’ according to equation (1) varies linearly with G” for a set value of the loss tangent, and thus, a G” range of less than 1,000 kPa corresponds to a G’ of less than 1,250 kPa when the loss tangent is 0.8. For example, when values lower than 1,000 are used as G” in equation (1), such as G” = 100, 10, or 1, G’ is less than 1,250 such as G’ = 125, 12.5, or 1.25, respectively. Thus, the range of less than 1,250 kPa overlaps with the claimed Young’s modulus range. In the case where the claimed ranges “overlap or lie inside ranges disclosed by prior art” a prima facie case of obviousness exists. See MPEP §2144.05.
Regarding claim 2, the Young’s modulus range for SBR suggested by Park modified by Oshima, as discussed regarding claim 1 above, overlaps with the claimed range. In the case where the claimed ranges “overlap or lie inside ranges disclosed by prior art” a prima facie case of obviousness exists. See MPEP §2144.05.
Regarding claim 3, Park teaches the copolymer may include an acrylic acid-based monomer unit (corresponding to the claimed copolymer of polyacrylic acid) (Park, [0047]).
Regarding claim 4, Park teaches the copolymer may include a vinyl alcohol monomer unit (corresponding to the claimed polyacrylic acid-based copolymer is a copolymer of polyacrylic acid and polyvinyl alcohol) (Park, [0047]).
Regarding claim 5, the copolymer is of the general formula shown below, where R1 – R13 may be H, R’1 is CN, R’2 may be OH, M may be H, l is 1 – 5 mass %, m is 10 – 85 mass %, and n is 10 – 85 mass % (Park, [0044]-[0045]), which allows for the l fragment to be poly(cyanoethyl)vinyl ether (with a single unit mass of ~97.11 g/mol), the m fragment to be polyvinyl alcohol (with a single unit mass of ~44.05 g/mol), and the n fragment to be polyacrylic acid (with a single unit mass of ~72.06 g/mol);
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Greyscale
when the l, m, and n mass percent ranges, using the l, m, and n fragments described above, are converted to mol % ranges, polyacrylic acid is present in a content range of ~18.4 – ~91.8 mol % inclusive, as calculated by the examiner, which overlaps with the claimed range. In the case where the claimed ranges “overlap or lie inside ranges disclosed by prior art” a prima facie case of obviousness exists. See MPEP §2144.05.
Regarding claim 7, Park teaches the copolymer may be present at 1 to 20 % based on the total weight of the anode slurry (Park, [0069]) which overlaps with the claimed range. In the case where the claimed ranges “overlap or lie inside ranges disclosed by prior art” a prima facie case of obviousness exists. See MPEP §2144.05. The examiner notes that while Park does not explicitly limit the mass content of the additional polymer in the anode composition, Park discloses a method for producing an anode including 89 g of a silicon anode active material, 3.2 g of a carbon anode active material and 3 g total of binder (Park, [0132]), which corresponds to ~3.25 weight % of binder as calculated by the examiner and meets the claimed binder range.
Regarding claim 8, Park teaches the anode active material may be Si (corresponding to the claimed SiOx where x = 0), SiOx (0<x<2), or an Si-Y alloy wherein Y may be a group 14 element (corresponding to the claimed SiC as one skilled in the art would recognize C is a group 14 element) (Park, [0065]).
Regarding claim 9, Park teaches the anode active material layer may further include a conductive material which may be graphite (corresponding to the claimed carbon-based anode active material) (Park, [0073]).
Regarding claim 10, Park teaches the anode active material, which may be silicon or a silicon compound (as discussed regarding claims 1 and 8 above), may be contained in an amount of 60 – 80 % which meets the claimed range.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Park as applied to claim 1 above, and further in view of Kim et al. (US 2023/0197940), hereinafter “Kim”.
Regarding claim 6, Park teaches the copolymer may be included in the anode slurry in a range of 1 – 20 % as described regarding claim 7 above but is silent to the content range of the additional polymer (which may be SBR as described regarding claim 1 above).
However, Kim teaches a binder for a silicon-containing anode wherein the binder comprises a main aqueous binder which preferably comprises polyvinyl alcohol and polyacrylic acid and thus corresponds to Park’s copolymer, and a secondary rubber-containing binder which is preferably styrene butadiene for easy dispersion and excellent phase stability (Kim, [0015], [0091], [0101]). The main binder may be present in the anode binder in an amount of 80 to 99 parts, and the secondary binder may be present in an amount of 1 to 20 parts both by weight based on 100 parts by weight of the anode binder. When the main and secondary binders are within the above content ranges, the binder’s dispersibility is improved and will provide better adhesive force for a silicon-containing anode material (Kim, [0116]-[0118]). Thus, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the instant invention to add Kim’s binder composition ranges to Park’s copolymer (corresponding to Kim’s main binder as discussed above) and additional polymer (which may be SBR and thus corresponds to Kim’s secondary polymer) in order to improve the binder dispersibility during electrode fabrication and to provide superior adhesive force within Park’s silicon-containing anode active material as taught by Kim (Kim, [0118]).
The resulting anode, as suggested by Park modified by Oshima and Kim, would include the copolymer and SBR in a ratio range of 80:20 – 99:1 which the examiner converts to a ratio range of 1:0.25 – 1:0.01, which overlaps with the claimed range. In the case where the claimed ranges “overlap or lie inside ranges disclosed by prior art” a prima facie case of obviousness exists. See MPEP §2144.05.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Tani et al. (US 2023/0378438) teaches claim 6. Wang et al. (CN 109962239 A) teaches the PAA copolymer according to claim 4.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SIMRAN S SAUND whose telephone number is (571)270-0845. The examiner can normally be reached Monday-Friday 8am-5pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jonathan Johnson can be reached at (571) 272-1177. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/SIMRAN S. SAUND/Examiner, Art Unit 1734
/NICHOLAS A WANG/Primary Examiner, Art Unit 1734
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