DETAILED ACTION
Application 17/670154, “GLASS CERAMIC SEAL MATERIAL FOR FUEL CELL STACKS”, was filed with the USPTO on 2/11/22 and claims priority from a provisional application filed on 4/15/21.
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 1/28/26.
Response to Arguments
Applicant’s arguments filed on 1/28/26 have been fully considered, but are not persuasive. Applicant presents the following arguments.
Goedeke does not teach the glass ceramic seal composition comprising 0.5 to 2 mol% La2O3. In response, this deficiency is cured by Mayumi.
The Office has previously argued that La2O3 is obvious to include in the composition of Goedeke at least because it is taught as an adhesion promoting additive by Mayumi. Applicant responded by arguing in after-final arguments that the Office had not established that this function would translate to the seal composition of Goedeke, but the advisory action indicated that argument was not found persuasive at least because there is no supporting evidence of record, and the submission or identification of such evidence is applicant’s burden. Applicant currently argues on pages 9-10 of the 1/28/26 that the evidence to weigh against the prima facie case of obviousness includes factors such as: applicant’s realization that B2O3 and La2O3 both function as network formers that enhance viscosity; the presently claimed composition exhibits high chemical stability and enhanced structural viscosity without becoming refractive; the cited art does not recognize the beneficial synergy between boron trioxide and lanthanum oxide. In response, it has been held that “[a]rguments presented by applicant cannot take the place of evidence in the record” (MPEP 2145 I, 716.01(c) II). Here, applicant’s description of the advantages associated with the invention do not sufficiently rely on the as-filed specification for evidentiary support. Additionally, the basis for the prima facie case of obvious is, at least in part, that the glass seal composition of Goedeke, or Goedeke in view of Mayumi, would provide a similar sealing function and the differences are known/obvious over the cited art; therefore, the claimed invention is also obvious. The arguments presented by applicant, even if taken as evidence, do not appear to analyze the disclosure of Goedeke or Mayumi, and explain with appropriate evidence, such as expert opinion evidence and/or experimental evidence, why the presently claimed glass composition is indeed substantially and unexpectedly different in function or behavior from those suggested by the cited art. See MPEP 716 for more information on the requirements regarding affidavits or declarations and other evidence for traversing rejections.
Regarding claim 4, as demonstrated in applicant’s Table 1, small amount of B2O3 provides improved chemical stability compared to the 7 mol% utilized in the Goedeke example 6. In response, applicant’s Table 1 characterizes the “Glass 3” embodiment, which includes 6.5 mol% B2O3 as desirable, and provides no example which includes 7.0 mol% B2O3, such as in Goedeke example 6. Thus, the Table 1 does not provide evidence to demonstrate that the Goedeke example 6 embodiment is less desirable and/or substantially different, particularly because of the inclusion of 7.0 mol% B2O3.
Moreover, the broader disclosure of Goedeke (e.g. Goedeke claim 1) allows for lower contents of B2O3, thus selection of a smaller amount of B2O3 is prima facie obvious. As described above, the evidence of nonobviousness is not found to be sufficient. As described in MPEP 2123 II, the whole of a disclosed range remains obvious even if disclosed examples [lying outside applicant’s claimed range] are provided. Here, the prior art is not required to demonstrate that the lower portion of the B2O3 range disclosed at Goedeke claim 1 is more desirable or favorable in order for that portion to be prima facie obvious.
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.
Claim 1, 2, 4, 7, 8, 15, and 26 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Goedeke (US 2013/0272774) and Mayumi (US 2011/0053753).
Regarding claim 1-2 and 4, Goedeke teaches a glass ceramic seal (see title) formed from a precursor material (paragraph [0061-0062]).
Goedeke broadly teaches the material containing SiO2, B2O3, Al2O3, CaO and MgO as its primary oxide constituents in amounts that overlap the claimed ranges, with other oxide constituents being optionally included in amounts of 0-10 mol% (see Goedeke claim 1).
Goedeke further teaches various exemplary embodiments, the closest to the claimed invention appears to be Example No. 6 which includes in mol%: 44% SiO2, 7% B2O3, 1% Al2O3, 22% CaO, 22% MgO, 1% Cs2O and 3% Y2O3 (see Table 1). This composition may be interpreted to include 90% of a primary component comprising SiO2, B2O3, Al2O3, CaO, MgO and Cs2O, and 10% of a secondary component comprising B2O3 and Y2O3 [10% = 3% + 7%]. This deviates from the claimed invention only in that it includes 1% Cs2O (disclosed as an optional constituent which may be 0% at paragraph [0048]) and the B2O3 content is 7%, higher than the 0.25 to 6.5 mol% B2O3 limit of claim 1 as amended on 1/28/26 and the 0.25 to 1.25 mol% range of claim 4.
As described in MPEP 2144.05 II, “[g]enerally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation… It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions.” Here, the claimed invention is found to be prima facie case obvious because the invention of Goedeke as broadly disclosed provides oxide constituent content ranges which are largely overlapping in scope with the claimed ranges, the specific Example No. 6 of Goedeke is very close to the claimed invention – deviating only by including a small amount of Cs2O and the content of B2O3 being marginally higher [7.0 of Goedeke vs 6.5 as the upper limit of the B2O3 concentration of claim 1] than the claimed range, and no evidence of record demonstrates that the claimed invention is critically different from the invention disclosed by Goedeke – particularly the Example No. 6 which is close enough to the claimed invention that substantially the same sealing properties would be expected.
The 7.0 B2O3 content of Goedeke Example 6 is more substantially higher than the 0.25 to 1.25 mol% range of claim 4; however, the broader disclosure of Goedeke (e.g. Goedeke claim 1) still suggests this range as suitable and thus prima facie obvious.
Regarding the 1/28/26 amendment to claim 1, Goedeke does not appear to teach wherein the precursor material comprises 0.5 to 2 mol% of La2O3.
In the fuel cell art, Mayumi teaches that it is desirable to include La2O3 in a glass sealing composition at an amount of 0.1 to 3 mass%, or more narrowly 0.1 to 1 mass%, for the benefit of improving adhesiveness to metals (paragraphs [0035-0036]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to add 0.1 to 3 mass%, or more narrowly 0.1 to 1 mass%, of La2O3 into the precursor material of Goedeke for the benefit of improving adhesiveness to metals as taught by Mayumi. The claimed range of 0.5 to 2 mol% is found to be obvious because the prior art range lies within, or at least substantially overlaps the claimed range after conversion from mass% to mol%.
Regarding claim 7 and 26, Goedeke remains as applied to claim 1. Goedeke further teaches wherein the glass ceramic seal comprises less than 0.25 mol % of Ba, Sr, BaO and SrO (abstract; paragraph [0022]; see also Example No. 6).
Regarding claim 8, Goedeke remains as applied to claim 1. Goedeke further teaches wherein the glass ceramic seal comprises less than 0.25 mol % of Na and K (paragraph [0047]; see also Example No. 6).
Regarding claim 15, Goedeke remains as applied to claim 1. Goedeke further teaches wherein the glass ceramic seal has a sintering temperature of less than 1000° C (paragraph [0062]; see also Example No. 6).
Claim 9 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Goedeke (US 2013/0272774), Mayumi (US 2011/0053753) and Kwon (US 2005/0008915).
Regarding claim 9, Goedeke remains as applied to claim 1. Goedeke does not expressly teach wherein the precursor material comprises 0.25 to 0.5 mol% of SrO and 0.5 to 1.5 mol% of BaO.
However, Goedeke does teach that the material may include BaO and SrO as impurity constituents, which sometimes “cannot be avoided completely”, preferably at less than 0.2% total (paragraph [0022]).
It has been held that “[g]enerally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical (MPEP 2144.05 II). Here, the content of the BaO and SrO may be low (0.5 and 0.25 mol%, respectively) and there is no evidence of record tending to prove that the precursor material including BaO and SrO in the claimed content would have substantially effect on the precursor material, compared to that which contains BaO and SrO as impurity constituents as taught by Goedeke.
Alternatively, in the fuel cell art, Kwon teaches chemicals used in manufacture of fuel cell may generally have impurities of less than 1% or 2% by weight or greater than 0.2% or 0.5% by weight, and that low impurity materials tend to be more expensive (paragraph [0022]).
Thus, although Goedeke teaches that the content of BaO and SrO is preferably less than 0.2% total, it would have been obvious to a person having ordinary skill in the art at the time of invention to produce the precursor material with higher content of BaO and SrO, such as within the claimed range, by using lower cost materials which may have higher impurity contents in view of Kwon.
Claim 10 and 11 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Goedeke (US 2013/0272774), Mayumi (US 2011/0053753) and Pinckney (USP 7410921).
Regarding claim 10 and 11, Goedeke remains as applied to claim 1. Goedeke does not expressly teach that the glass ceramic seal comprises, by volume, from 55% to 85% of a crystalline phase and from 45% to 15% of an amorphous phase, or more narrowly from 60% to 80% of the crystalline phase and from 40% to 20% of the amorphous phase.
However, Goedeke does teach that the glass ceramic seal may comprise a glass-ceramic mixture wherein an amorphous phase is partially or completely converted to crystalline (paragraph [0005]), with MgO or other oxide additives specifically contributing to crystallization (paragraph [0032, 0037-0038]), so as to provide a product with more than 50% crystallization (paragraph [0040]).
Moreover, in the fuel cell art, Pinckney teaches that the glass ceramic may be configured to have a residual glass content of less than 20% (c2:47-52 and c4:1-6), suggesting a crystalline phase range which overlaps the range of claim 10 [at 80-85% crystalline phase] and is infinitely close to the range of claim 11 [with “less than approximately 20%” of Pinckney being substantially equivalent to the 20% end point of the range of claim 11]. Pinckney further teaches that degree of crystallization is a result-effective variable with glass-ceramics with a high crystalline content are particularly well suited for sealing application (c4:53-58).
It would have been obvious to a person having ordinary skill in the art at the time of invention to configure the glass ceramic seal of Goedeke such that that the glass ceramic seal comprises, by volume, from 55% to 85% of a crystalline phase and from 45% to 15% of an amorphous phase, or more narrowly from 60% to 80% of the crystalline phase and from 40% to 20% of the amorphous phase, since highly crystalline glass-ceramics are achievable and a high degree of crystallinity, such as the claimed range, is associated with desirable sealing properties as taught by Pinckney.
Claim 12-14 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Goedeke (US 2013/0272774), Mayumi (US 2011/0053753) and Pinckney (USP 7410921).
Regarding claim 12-14, Goedeke and Pinckney remain as applied to claim 10. Goedeke further teaches that certain embodiments of the glass ceramic seal may comprises diopside and wollastonite phases (paragraph [0083; Goedeke claim 7), but does not expressly teach wherein the crystalline phase comprises primarily diopside crystals with some wollastonite (c4:33-38; e.g. Example 13 or 18).
Pinckney further teaches wherein the crystalline phase comprises primarily diopside crystals with some wollastonite (c4:33-38; e.g. Example 13 or 18 which is diopside with minor amount of wollastonite). Pinckney further teaches that including some wallostonite allows for tailoring thermal expansion matches to specific substrates (c5:42-56).
Moreover, in the fuel cell art, Mayumi teaches that glass compositions including CaO-MgO-SiO2 systems are suitable for the formation of diopside type crystal phase, that diopside is a “highly expansive crystal” [interpreted to suggest desirable thermal match], that a composition which chiefly precipitates diopside is likely to undergo less transformation of crystalline phase at firing temperatures and to exhibit stabilization in the strength of the bulk prepared by crystallization, and that the formation of diopside can be influenced or controlled by manipulating the SiO2 content of the glass (paragraphs [0022-00233]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to configure the glass ceramic to include a crystalline phase comprised of primarily diopside for the benefit of desirably matching thermal characteristic of the SOFC, providing strength, and stability as taught by Pinckney and/or Mayumi. Diopside with some wollastonite as the manipulation of the crystal phases is associated with tailoring the thermal matching, and diopside with minor wollastonite, particularly, is taught as suitable at least at Pinckney Example 18, thus this configuration is also found to be obvious as being desirable or at least a known variant.
Further regarding claim 14, the cited art is silent as to the crystalline phase further comprises anorthite, wollastonite, and magnesium aluminium silicate crystals.
However, as described in MPEP 2141 III, “The prior art reference (or references when combined) need not teach or suggest all the claim limitations. However, Office personnel must explain why the difference(s) between the prior art and the claimed invention would have been obvious to one of ordinary skill in the art. The “mere existence of differences between the prior art and an invention does not establish the invention’s nonobviousness.”
Here, claim 14 does not specify a relative amount of these constituents; therefore, they may be present as only minor constituents with the crystalline phase being primarily diopside crystals, which is taught by the cited art.
The record does not suggest a substantial difference in performance or function of the glass ceramic phase which is caused by the presence of a minor amount of anorthite, wollastonite, and magnesium aluminium silicate crystals within a diopside majority crystal system, compared to the systems of Goedeke, Pinckney and/or Mayumi which may be, for example, diopside with a minor amount of wollastonite.
Therefore, claim 14 is found to be obvious because either, i) the glass ceramic compositions of the prior art embodiments would comprise small amounts of anorthite, wollastonite, and magnesium aluminium silicate crystals due to having similar precursor composition and sintering conditions as the claimed invention, or ii) if the prior art compositions indeed lacked all of anorthite, wollastonite, and magnesium aluminium silicate crystals, there is no evidence to indicate that such a difference is functionally significant considering that the cited art teaches embodiments comprised of primarily diopside with “minor” amounts of other crystal types, and claim 14 is not limited with respect to the amount of the named crystal types.
Claims 1, 16 and 21-23 is/are rejected under 35 U.S.C. 103 as being obvious over Gasda (US 2019/0372132) in view of Goedeke (US 2013/0272774) and Mayumi (US 2011/0053753).
Regarding claims 1, 16 and 23, Gasda teaches a fuel cell stack (Figures 1A-1C; 3A-3C), comprising: interconnects stacked over one another; a seal disposed between the interconnects; and solid oxide fuel cells disposed between the interconnects (Figures 1A-1C; 3A-3C ; see also paragraphs [0017, 0031] regarding fuel cells disposed between stacked interconnects and paragraphs [0021, 0023, 0045-0048] regarding a seal being disposed between the interconnects), wherein: the interconnects comprise at least two fuel inlets separated by a neck portion and at least two fuel outlets separated by a neck portion (Figures 4A, 4B; paragraph [0038]).
Gasda further teaches the seal comprising a glass ceramic material (paragraph [0048]), but does not expressly teach wherein the glass ceramic seal is the glass ceramic seal of claim 1.
In the fuel cell art sealing material art, Goedeke suggests sealing materials of, or similar to, the composition required by claim 1 (see rejection of claim 1 over Goedeke). Goedeke further teaches that his inventive sealing materials are useful as high-temperature sealing agents for fuel cells (paragraph [0002]) and have various engineering advantages, such as high-temperature stability and expansion characteristic matching, associated therewith (paragraphs [0018-0019]).
The replacement of the glass ceramic sealing material of Gasda with a glass ceramic sealing material taught by Goedeke would merely require the simple substitution of one known sealing material for another to yield the predictable result of an effective high temperature metal seal; therefore, a prima facie case of obviousness as described in MPEP 2141. Moreover, such a modification may provide additional engineering advantages or improvements as taught by Goedeke; therefore, additional rationale exists for performing such a modification of the Gasda fuel cell in view of Goedeke. Finally, since seal material of claim 1 is found to be obvious over Goedeke for reasons given in the rejection of claim 1, the invention of claim 16 as a whole is also found to be obvious over the combination of Gasda and Goedeke
Regarding claim 21, the cited art remains as applied to claim 16. Goedeke further teaches that the glass ceramic seal comprises primarily diopside (paragraph [0083]).
Regarding claim 22, the cited art remains as applied to claim 16. Goedeke further teaches that the glass ceramic seal is substantially free of sodium, potassium, barium, strontium and oxides thereof (abstract; paragraph [0022, 0047]; see also Example No. 6). Goedeke further lists the expected crystal types as omitting feldspar (paragraph [0083]). The omission of feldspar is therefore implicit, or at least obvious as feldspar is not disclosed, desired or required.
Claims 17 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Gasda (US 2019/0372132), Goedeke (US 2013/0272774), Mayumi (US 2011/0053753) and Pinckney (USP 7410921).
Regarding claim 17, the Gasda and Goedeke remain as applied to claim 16. Claim 17 further requires that a coefficient of thermal expansion of the glass ceramic seal is within +/−10% of a coefficient of thermal expansion of the interconnects, which is not expressly taught by Gasda, Goedeke or Pinckney.
However, Gasda does teach wherein: a coefficient of thermal expansion of the interconnects is within +/−10% of a coefficient of the thermal expansion of another component of the solid oxide fuel cell [the electrolyte] and characterizes such a range as indicating “similar coefficient of thermal expansion” (paragraph [0042]).
Gasda further teaches that his interconnects are formed from chromium alloy materials (paragraph [0032]), while Goedeke teaches that his inventive seal material is configured to have a coefficient of thermal expansion compatible with chromium steels and alloys (paragraph [0019]).
Additionally, Pinckney does teach that his inventive seal materials may be configured to “have a thermal expansion closely matched to that of the metal or ceramic substrate” (c4:56-58).
Therefore, the requirement that the thermal expansion of the glass ceramic seal is within +/−10% of a coefficient of thermal expansion of the interconnects is found to be obvious over the cited art because: i) the glass ceramic composition taught by the cited art are substantially the same as that claimed compositionally, thus the same or nearly the same thermal expansion characteristic would be expected, ii) the prior art sealing materials expressly taught to be configurable to have a thermal expansion characteristic which “closely matches” that of an adjacent metal or ceramic material, thus the optimization of thermal expansion characteristic of the sealing material to match that of body to which the material is to be attached is suggested, and iii) it would have been obvious to a person having ordinary skill in the fuel cell art at the time of invention to configure stack such that the glass ceramic sealing material matches the thermal expansion coefficient of the other stack components, such as the SOFCs and the interconnects, by mutual optimization of all three components for the benefit of avoiding problems with thermal mismatch as the SOFC is raised to high-temperature operation.
Such a desirable embodiment could be achieved by manipulating the thermal expansion coefficient of any or all of the three named stack components, rather than just the glass ceramic material of claim 1. Accordingly, the claimed matching embodies an obvious design goal rather than a specific and defined structure which could be distinguished from that of the prior art.
As to the limitations of claim 17 drawn to the crystalline/amorphous ratio and the crystal type of the glass ceramic seal, these limitations are obvious over the cited art for reasons previously given in the rejection of claims 10-14.
Conclusion
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/JEREMIAH R SMITH/Primary Examiner, Art Unit 1723