DETAILED ACTION
Application 17/568303, “Separator Having Excellent Thermal Conductivity And Electrochemical Element Using The Same”, was filed with the USPTO on 1/4/22 and claims priority from a foreign application filed on 1/5/21.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This Office Action on the merits is in response to communication filed on 12/9/25.
Response to Arguments
Applicant’s arguments filed on 12/9/25 have been fully considered, but are unpersuasive or moot in view of the new ground(s) of rejection.
It is noted that Cho suggests a silicon oxide film of 0.5 to 20 nm thickness, teaching or suggesting the 2 nm to 50 nm silicon oxide thickness requirement, and Zhou, now applied in the rejection of claim 1 due to the amendment, teaches a layer similar to the claimed coating layer which has a binder content of 1 to 30%, such as 2%, thereby suggesting the claimed 0.2 to 4 wt% binder range.
Applicant further presents the following arguments.
None of the cited references teach all of the recited features in combination. In response, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Here, applicant’s argument that none of the references teaches or suggests the claimed combination of features is not found persuasive because the Office action describes how the cited art is used to address each of the presently claimed limitations.
Liu does not suggest silicon particles having an oxide film shell. In response, a different reference is relied on to teach this feature in the art rejections.
Liu and Cho fail to recognize the advantages of improved heat dissipation and increased breakdown voltage demonstrated in applicant’s Table 1. In response, as described in MPEP 2144 IV, “The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant.”
Additionally, it is noted that applicant’s Examples appear to be narrower in scope than applicant’s presently claimed invention. For example, the Examples 1-8 appear to each utilize core-shell silicon particles having an average particle size of 0.5 or 1 micron [diameter?] applied onto the separator substrate with a 2.6 micron thick active layer. Therefore, if applicant’s argument is intended to be an argument of unexpected results intended to overcome the rejection by secondary considerations, the provided evidence is insufficient to demonstrate that any noted advantage would be achieved over the breadth of the claimed invention.
Cho does not teach using silicon particles having a silicon oxide layer other than as a negative active material. Moreover, impermissible hindsight is required to apply the oxide coating of Cho to the silicon particles of Liu. In response, since the Liu silicon particles in the separator layer are functional to be lithiated and delithiated by lithium ions (paragraph [0060]), they are susceptible to the same dimensional changes that silicon used as a negative electrode active material is susceptible to. Therefore, the improvement suggested by Cho, i.e. the use of oxide coating for improved resiliency, appears to be relevant to the Liu silicon particles and the modification is prima facie obvious. Impermissible hindsight is not required because Liu teaches lithiation and delithiation of silicon particles, and Cho expressly teaches that the silicon oxide coating addresses volume expansion problems associated with this process (c8:8-20). Only knowledge within the references and/or the ordinary skill of the artisan is required to produce the modification; therefore, impermissible hindsight has not been utilized.
Cho does not suggest the large content (50 to 99.9 wt%) of inorganic particles in the coating layer. In response, Liu is relied on to teach this feature; therefore, Cho need not also teach the same feature.
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 of this title, 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, 3, 5-7, 10-11, 13-16 and 18-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu (US 2022/0115689) in view of Cho (USP 10586976), Sung (US 2018/0315969) and Zhou (US 2019/0319239).
Regarding claim 1, 3, 5-7 and 10, Liu teaches a separator (Figure 1) comprising a porous substrate (item 1) and a coating layer (item 2) formed on one or both surfaces of the porous substrate (see Figure 1; paragraph [0097] where “functional film layer” is the claimed coating layer). Liu further teaches that the porous substrate may comprise a polyolefin such as polyethylene or polypropylene (paragraph [0094]), and that the functional film layer may comprise a binder such as polyvinyl alcohol (paragraph [0098]) and an inorganic material which may comprise one or more materials such as silicon, silicon oxide or aluminum (paragraphs [0060, 0097]), with a preferred diameter of 200 to 2000 nm (paragraph [0006]). The “optional organic particles” of claim 1 are not required.
Claim 1 further requires wherein the separator is not electrically connected with electrodes. This feature is suggested by Liu’s teaching of lone functionalized separator, such as at Liu claim 1 and Figure 1, which are independent from Liu’s teachings of a whole battery, such as at Liu claim 15 and Figure 3.
Liu teaches that the inorganic particles may comprise materials such as silicon and silicon oxide which are capable of reversibly alloying with lithium to form lithium alloys functional as active material (paragraphs [0057, 0060, 0097, 0190]), but does not appear to teach that the inorganic particles comprise core-shell silicon particles having an oxide shell, with, as required by the 12/9/25 amendment to claim 1, a 2 nm to 50 nm thickness.
In the battery art, Cho teaches that conventional silicon particles may be prone to crack and deterioration when alloying with lithium (c4:10-29), and further teaches that an alloyable silicon particle comprising a silicon core and a silicon oxide shell (Fig. 5B; c8:1-3, c8:21-14; Cho claim 5) of 0.5 to 20 nm thickness (c8:18-20) provides high capacity and mechanical resiliency (abstract; c2:26-32, c2:60-61).
It would have been obvious to a person having ordinary skill in the art at the time of invention to replace some or all of the Si or silicon oxide particles suggested by Liu with Si/SiO core-shell particles as taught by Cho for the benefit of improving the capacity and/or mechanical resiliency of the battery in view of Cho. Moreover, the requirement that the thickness of the silicon oxide shell is between 2 and 50 nm is found to be obvious because the 0.5 to 20 nm thickness range taught by Cho largely overlaps and substantially lies within the claimed range (see MPEP 2144.05 regarding obviousness of overlapping ranges).
Liu does not expressly teach that the coating layer may include other inorganic particles selected from one or two or more selected from a metal oxide, a metal nitride, a metal carbide, a metal carbonate, a metal hydrate, and a metal carbonitride, such as boehmite
In the battery art, Sung teaches that a separator may comprise a coating layer (abstract, paragraph [0033]), wherein the coating layer may comprise a combination of inorganic particles and boehmite (paragraph [0047]), with the boehmite particles included for the benefit of improved heat conductivity even when added in a small amount, lower cost, and safety (paragraph [0059, 0061, 0007]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to further include an other inorganic particle, such as boehmite particles, in the coating layer for the benefit of improving heat conductivity, economy and safety as taught by Sung.
Claim 1 further requires wherein a content of the core-shell silicon particles is 50 to 99.9% by weight of a total content of the coating layer [including the silicon particles, other inorganic particles and optionally organic particles].
Liu further teaches wherein a content of the silicon particles makes up about 80 to 99% of the functional layer [readable on the coating layer] (paragraph [0090]).
The requirement that 50 to 99.9% by weight of a total content of the coating layer is core-shell silicon particles is found to be obvious over the cited art because the silicon particle content suggested by Liu lies within the claimed range, noting that Cho provides the rationale for replacing silicon particles with core-shell silicon particles.
It is further noted that the addition of other inorganic particles in view of Sung would reduce the content of the core-shell silicon particles downward from the 80-99% range taught by Liu. Sung teaches a preferable inorganic particle:boehmite range of 85:15-95:5 (paragraph [0051-0052]). Applying this range suggests that the core-shell silicon particles of Liu-Cho may be include at least at about 68 wt % [80% lower end of range of Liu multiplied by 85% in view of Sung]; therefore, even after replacing some of the silicon core-shell particles with boehmite in view of Sung, the core-shell silicon particles content would remain within or overlap the claimed 50 to 99.9% range, leaving it obvious.
Regarding the 12/9/25 amendment to claim 1, Liu teaches that the functional film layer may comprise a binder such as polyvinyl alcohol, but does not expressly teach that the content of the binder provides 0.2 to 4 weight percent of the functional layer [the coating layer].
In the battery art, Zhou teaches that a functional [coating] layer of a separator may comprise a material that can reversibly intercalate lithium and a binder (paragraphs [0005, 0042]), wherein between the intercalation material and the binder, the intercalation material makes up 70 to 99%, meaning 1 to 30% binder, for the benefit of balancing sufficient amount of intercalation material with sufficient adhesive strength (paragraph [0043]) with an exemplary binder content of 2 wt % (paragraph [0112]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to provide the binder of the coating layer in an amount within the range of 0.2 to 4 wt % because Zhou broadly teaches a binder content of 1 to 30%, teaches an exemplary binder content of 2 wt% which lies within the claimed range, and teaches the intercalation material/binder ratio as a result-effective variable suggesting obviousness for optimization by routine experimentation.
Regarding claim 7, the cited art remains as applied to claim 1. Liu further teaches wherein the content of the inorganic particles is 50 to 99.9% by weight of the total coating layer (paragraph [0090]; see also Example 1 at paragraphs [0151-0154] which teaches an embodiment wherein inorganic particles provide more than 50% of the mass of the dried functionalized [coating] layer).
Regarding claim 11, the cited art remains as applied to claim 1. Liu further teaches wherein the separator has a thickness lying within the range of 5 to 100 μm (paragraphs [0035] and [0037] together suggest a total separator thickness within the claimed range).
Regarding claim 13 and 14, the cited art remains as applied to claim 1. Liu further teaches the separator as a subcomponent of a lithium secondary battery comprised of a positive electrode, a negative electrode, the separator, and an electrolyte (e.g. paragraph [0039]).
Regarding claims 15 and 18-19, the cited art remains as applied to claim 1. The cited art teaches the structure described in process claims [such as the silicon particles having oxide shell, the binder, coating on one or both sides of a porous polyolefin substrate, mixture of the Si/SiO particles and another inorganic material of named species] as previously described in the rejection of product claims above, with the details of the rejections presumed to be incorporated herein as applicable.
As to the method of making the separator Liu further teaches preparing a dispersion solution comprising the functional layer constituents, coating the dispersion solution onto the porous substrate base, and drying the coated base to provide the separator (paragraph [0099-0104; 0151-0154]). Therefore, the claimed method is obvious over the cited art.
Regarding claim 16, the cited art remains as applied to claim 15. Claim 16 further requires “wherein the silicon particles having the oxide film shell are manufactured by friction of the silicon particles in an aqueous solution to oxidize the surface, or by plasma or corona treatment in air, ozone, or oxygen atmosphere to form a surface oxide layer”. This technique describes a method of making oxide coated silicon particles, not a method of making a separator, and is therefore only found to be limiting with respect to the structure implied. However, the structure implied does not appear to be different from that of the oxide coated silicon particles of the prior art (e.g. c8:21-24 of Cho; see also Shimura); therefore, claim 15 is found to be obvious over the cited art.
Claims 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu (US 2022/0115689) in view of Cho (USP 10586976), Sung (US 2018/0315969) and Zhou (US 2019/0319239), as applied to claim 1, and further in view of Gu (US 2019/0260001).
Regarding claim 12, the cited art remains as applied to claim 1. Liu does not appear to teach wherein the separator has a pore diameter in the range of 0.001 to 10 μm, and a porosity in the range of 5 to 95%.
In the battery art, Zhou teaches that a porous substrate of a separator may be configured to have an average pore size of 0.001 μm to 10 μm, and the porous substrate has a porosity of 5% to 95% (paragraph [0026]).
In the battery art, Gu teaches that a desirable separator may have a pore size of 0.01-50 μm and a porosity of 10-95% (paragraph [0027]), so as to provide desirable battery performance (paragraph [0047]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to configure the overall separator to have the claimed pore diameter and porosity values for the benefit of ensuring that the separator is porous enough to fulfill its normal function of allowing electrolyte and ions to pass therethrough to facilitate the electrochemical reactions of the battery, but robust enough to provide mechanical integrity of the battery, so as to provide desirable battery performance as taught by Zhou or Gu.
Claims 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over the combination of Liu (US 2022/0115689) in view of Cho (USP 10586976), Sung (US 2018/0315969) and Zhou (US 2019/0319239), as applied to claim 1, and further in view of Cho2 (US 2018/0034056).
Regarding claim 16, the cited art remains as applied to claim 15. Claim 16 further requires “wherein the silicon particles having the oxide film shell are manufactured by friction of the silicon particles in an aqueous solution to oxidize the surface, or by plasma or corona treatment in air, ozone, or oxygen atmosphere to form a surface oxide layer”. This technique describes a method of making oxide coated silicon particles, not a method of making a separator, and is therefore only found to be limiting with respect to the structure implied. However, the structure implied does not appear to be different from that of the oxide coated silicon particles of the prior art (e.g. of Cho); therefore, claim 15 is found to be obvious over the cited art.
For completeness of record, it is noted that in the battery art, Cho2 teaches that an oxide layer on a silicon core may be formed as a natural oxide, or alternatively could be provided by a process such as plasma treatment (paragraph [0044]).
It would have been obvious to provide oxide coated silicon particles by a process including plasma treatment in air, oxygen or ozone, as such techniques are known in the battery art as effective for forming such Si/SiO particles as taught by Cho2.
Relevant or Related Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure, though not necessarily pertinent to applicant’s invention as claimed.
Ye (CN 110247009) -teaches separator comprising Si particles which could be presumed to have a SiO layer disposed thereon;
Shimura (US 2015/0340679) -teaches Si/SiO/C carbon composite negative electrode active material;
Okuno (US 2015/0171396) -separator comprising porous surface layers on polyolefin microporous membrane substrate.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JEREMIAH R SMITH whose telephone number is (571)270-7005. The examiner can normally be reached on Mon-Fri: 9 AM-5 PM (EST).
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Milton Cano can be reached on 313-446-4937. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see https://ppair-my.uspto.gov/pair/PrivatePair. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JEREMIAH R SMITH/Primary Examiner, Art Unit 1723