Ex Parte Nakagawa et al

Patent Trial and Appeal Board

Mar 20, 2014

11047567 (P.T.A.B. Mar. 20, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE
THE PATENT TRIAL AND APPEAL BOARD

____________

Ex parte NOBUYOSHI NAKAGAWA, YOSHIHISA SUDA,
KOJI NISHIMURA, KUNITAKA YAMADA, and
OSAMU SHIMIZU
____________

Appeal 2012-005832
Application 11/047,567
Technology Center 1700
____________

Before LINDA M. GAUDETTE, MARK NAGUMO and
JAMES C. HOUSEL, Administrative Patent Judges.

HOUSEL, Administrative Patent Judge.

DECISION ON APPEAL

Appellants1 appeal under 35 U.S.C. § 134 from the Examiner’s
decision finally rejecting claims 1, 3, 7, 9, 11, 13, 15, 17, and 19. Claims 2,
4, 6, 8, 10, 12, 14, 16, 18, and 20 are pending but have been withdrawn from
further consideration. We have jurisdiction over the appeal under 35 U.S.C.
§ 6(b).

1 Appellants identify the Real Party in Interest in this appeal as Mitsubishi
Pencil Co., Ltd.
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We AFFIRM.2

STATEMENT OF THE CASE
The invention relates to a fuel cell having a structure which comprises
a unit cell in which respective layers of electrode/electrolyte/electrode are
formed on the surface of a base material having electrical conductivity, the
base material comprising a carbonaceous porous body comprising
amorphous carbon or a composite of amorphous carbon and carbon material
powder. Spec. 5:3-6:4 and 12:6-22. The base material is impregnated with
liquid fuel and an electrode surface formed on the outside surface of the base
material is exposed to air. Id. at 5:3-6:4.
Rejections
The Examiner maintains, and Appellants appeal, the following
rejections under 35 U.S.C. § 103(a):
1) Claims 1, 3, 7, 9, 17 and 19 as being unpatentable over Nakamura3
in combination with Zhang4;
2) Claim 11 as being unpatentable over Nakamura and Zhang, further
in view of Ren5; and

2 Our decision refers to Appellant’s Brief (App. Br.) filed July 25, 2011, the
Examiner’s Answer (Ans.) mailed October 25, 2011, Appellant’s Reply
Brief (Reply Br.) filed December 27, 2011, the Supplemental Examiner’s
Answer mailed February 8, 2012 (Supp. Ans.) and Appellant’s
Supplemental Reply Brief (Supp. Reply Br.) filed March 30, 2012.
3 US 4,500,395, issued February 19, 1985.
4 US 5,609,844, issued March 11, 1997.
5 US 2003/0049510 A1, published March 13, 2003.
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3) Claims 13 and 15 as being unpatentable over Nakamura and
Zhang, further in view of Koschany.6
Appellants separately argue claims 1, 3, 9 and 11 only. Br. 4-8.
Accordingly, dependent claims 7, 13, 15, 17 and 19 stand or fall with
independent claim 1 (37 C.F.R. § 41.37(c)(1)(vii)). Claim 1, representative
of the claimed invention, is reproduced below:
1. A fuel cell characterized by assuming a structure in which a
tabular base material having strength sufficient for holding its form
against compression force in a direction parallel to a surface of the
tabular material comprises a carbonaceous porous body comprising
amorphous carbon or a composite of amorphous carbon and carbon
material powder and having electrical conductivity and which
comprises a unit cell in which the respective layers of
electrode/electrolyte/electrode are formed on the surface of the base
material or a connected assembly prepared by connecting two or more
of the unit cells and in which the base material is impregnated with
liquid fuel and an electrode surface formed on the outside surface of
the base material is exposed to air.
App. Br. 8, Claims App’x.
ANALYSIS
After careful consideration of the respective positions of the Examiner
and Appellants, we find a preponderance of the evidence supports the
Examiner’s obviousness conclusion with regard to the proposed combination
of Nakamura and Zhang. We will sustain the Examiner’s Section 103(a)
rejections for the reasons expressed in the Answer with the comments below
added for emphasis.

6 US 6,890,675 B2, issued May 10, 2005.
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Claim 1
The Examiner finds Nakamura teaches a fuel cell having an anode
comprising an electrically conductive, carbonaceous porous body
impregnated with liquid fuel, in particular methanol. Supp. Ans. 4-5. The
Examiner finds Nakamura’s carbonaceous porous body is “a tabular base
material having strength sufficient for holding its form against compression
force in a direction parallel to a surface of the tabular material” based on a
comparison of the porosity, pore size and plate dimensions of Nakamura’s
body with the body discussed in Appellants’ Specification. Id. at 5-6. The
Examiner finds Nakamura’s carbonaceous porous body is coated with
platinum, and equates the platinum to Appellants’ anode. Id. at 5. The
Examiner acknowledges Nakamura does not disclose a unit cell. Id.
Nonetheless, the Examiner finds it would have been obvious to one of
ordinary skill in the art to use Nakamura’s anode in a fuel cell for the benefit
of generating electrical power. Id. The Examiner finds that a fuel cell
necessarily has layers of electrode/electrolyte/electrode that would be
formed on the surface of Nakamura’s base material, and the “electrode
surface formed on the outside surface of the base material would be capable
of being exposed to air.” Id.
Appellants assert that, “because the carbon plate 10 [of Nakamura] is
both coated and impregnated with the platinum, an ordinarily skilled artisan
would understand that the entire carbon plate 10 would thus become an
electrode.” App. Br. 5. However, Appellants contend it is not clear what
Nakamura contemplates as the overall fuel cell structure. Id. Appellants
further contend that since at least some prior art fuel cells use a liquid
electrolyte, the respective layers of electrode/electrolyte/electrode would not
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necessarily be formed on Nakamura’s carbon plate. Id. Appellants further
argue the Examiner “[did] not point out a single prior art disclosure of a fuel
cell formed by forming respective layers of electrode/electrolyte/electrode
on a base material.” Id. Moreover, Appellants argue “the Examiner has not
set forth any reasoning as to why an ordinary skilled artisan would modify
the fuel cell suggested by Nakamura to expose one of its electrodes to air as
recited in claim 1.” Id. at 6.
Appellants’ arguments are not persuasive of harmful error. In
rebuttal, the Examiner cites Dufner7 as evidence that a fuel cell necessarily
has an anode, a cathode and an electrolyte. Supp. Ans. 10. The Examiner
finds Dufner teaches electrochemical cells are commonly used in a fuel cell
configuration to produce electrical energy. Id. The Examiner further finds
electrochemical cells generally include an anode and cathode separated by
an electrolyte, and the anode and cathode are separated by different types of
electrolytes depending on operating requirements and limitations of the
working environment of the fuel cell. Id. The Examiner also finds Dufner
teaches a fuel cell necessarily employs a reducing fluid such as hydrogen, at
the anode and an oxidizing fluid, such as oxygen or air, at the cathode. Id.
at 12. Accordingly, Dufner reasonably supports the position that any fuel
cell, including those using a liquid electrolyte, necessarily has layers of
electrode/electrolyte/electrode, and that the cathode of the fuel cell uses air
or oxygen. Indeed, contrary to their own fuel cell structure argument,
Appellants disclose,
[i]n general, a fuel cell comprises a cell part on which an air electrode
layer, an electrolyte layer and a fuel electrode layer are laminated, a

7 US 6,024,848, issued February 15, 2000.
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fuel-supplying part for supplying fuel as a reducing agent to the fuel
electrode layer and an air-supplying part for supplying air as an
oxidizing agent to the air electrode layer, and it is an electric cell in
which electrochemical reaction is caused in a cell between fuel and
oxygen in the air to obtain electric power in the outside.

Spec. 1:16-24. Likewise, Zhang’s Figure 2 shows a fuel cell with electrodes
52, 54 and Zhang teaches fuel cells are usually gaseous or liquid, and
oxygen or air is the oxidant. Zhang, Fig. 2, and 3:21-33.
Appellants further argue Nakamura is silent concerning the plate’s
porosity after impregnation with platinum and thus is unclear how the liquid
fuel is intended to interact with Nakamura’s electrode. As such, Appellants
contend it cannot be concluded that Nakamura’s electrode is impregnated
with fuel during use in a fuel cell. App. Br. 5. We disagree. The Examiner
finds Nakamura teaches a plate porosity between 30% to 60%, the
micropores and through holes of Nakamura’s plate are impregnated with
platinum, and the electrode has an electrochemical oxidation activity of
methanol with respect to the platinum. Ans. 11-12, referring to Nakamura,
3:42, 4:29-36, 7:29-42 and Fig. 7. Since platinum impregnates Nakamura’s
porous plate and provides electrochemical oxidation activity of methanol,
the Examiner concludes, and we agree, that it is reasonable to expect the
methanol solution also impregnates the porous plate so the methanol can be
oxidized using the platinum in the pores of the plate. We note Nakamura
discloses the relationship between the mean pore diameter and the surface
area of the platinum coating, which we take as an indication that the plate
remains porous even after platinum coating. Nakamura, Fig. 9, and 3:26-30.
Furthermore, Nakamura controls the platinum coating to a
thickness “t”. Nakamura, 6:35-64. In Nakamura’s Figs. 5 and 6,
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impregnated platinum coating layer (30) has a relatively small thickness “t”,
whereas a relatively large portion of the porous carbon plate (10) is not
impregnated with platinum. Appellants admit that “an ordinary skilled
artisan would understand that the entire carbon plate 10 [of Nakamura]
would thus become an electrode.” App. Br. 5. Given Nakamura’s plate
porosity of 30% to 60% and pore sizes less than 50 µm, e.g., about 10 µm, it
is reasonable to expect that methanol solution impregnates Nakamura’s
entire electrode. Nakamura, 3:42, 3:46-48 and 6:16. Indeed, a porosity of
30% to 60% and a pore size of about 10 µm are within the scope of
Appellants’ disclosed and claimed ranges for the carbonaceous porous body.
See Spec. 6:15-20, 13:20-25, 14:2-5, and claim 3.
Appellants next argue “Zhang makes no mention of preparing an
electrode of a porous body.” App. Br. 6. However, Appellants fail to direct
our attention to any support for this argument in Zhang. To the contrary, the
Examiner finds “Zhang teaches a gas diffusion layer comprising amorphous
carbon.” Ans. 6. In fact, Zhang teaches the electrode including amorphous
carbon permits gas diffusion as depicted in Figure 2.
Appellants further argue that one of ordinary skill in the art would
understand that Zhang’s amorphous carbon has higher electric resistance
than Nakamura’s carbon black or graphite and is more unstable, and thus,
would not substitute Zhang’s amorphous carbon in place of Nakamura’s
carbon black or graphite. App. Br. 6. Appellants cite to Figure 3 and
accompanying text of a paper excerpted from the journal entitled “Physical
Review” and argues that resistivity decreases as the type of carbon structure
varies from cokes to graphite. Reply Br. 1. Appellants argue amorphous
carbon in the porous state would be expected to have an even higher
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resistivity because “considering a linear current root in the porous body,
parts of a length corresponding to a cubit root of the porosity is not
conductive.” Suppl. Reply Br. 1.
This argument fails to persuade us of harmful error. The Examiner
finds that substituting Zhang’s amorphous carbon for Nakamura’s carbon
black would yield predictable results of diffusing a reactant gas through a
fuel cell electrode. Suppl. Ans. 15-16. Claim 1 requires the carbonaceous
porous body has “electrical conductivity”. Neither Appellants’ claims nor
Specification recites any numerical level of electrical conductivity.
Nakamura’s fuel cell electrode comprises a porous body of carbon, graphite
or a mixture thereof and is electrically conductive. Nakamura, 1:44-49 and
3:34-40. Further, Zhang’s fuel cell electrodes comprise amorphous carbon
and are also electrically conductive. See Zhang, Fig. 2, 2:66-3:1. Not only
does Zhang mention coke and graphite as prior art electrode materials,
Zhang teaches an improved amorphous carbon that is easily manufactured in
a simple, high yield and, in particular, is used for either electrode of a fuel
cell. Zhang, abstract, 1:49-56, 2:18-21, 2:59 to 3:50 and Fig. 2.
Additionally, similar to Nakamura, Zhang teaches that in a fuel cell
electrode, platinum is captured in a carbon matrix. Zhang, 3:43-46.
Therefore, it is reasonable to expect substituting Zhang’s amorphous carbon
for Nakamura’s carbon black would yield an electrically conductive body,
precisely as required in claim 1. Appellants’ citation of the “Physical
Review” journal article lacks persuasive force since this teaching fails to
establish amorphous carbonaceous bodies are not electrically conductive.
Appellants next cite Examples 1 and 2 of the Specification and allege
an unexpected result of using methanol solutions having higher
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concentrations up to 20 mol/l (M) is obtained using a carbonaceous porous
body comprising amorphous carbon. App. Br. 6, Reply Br. 1-2, Supp. Reply
Br. 2. Appellants cite an excerpt from the textbook entitled “Polymer
Membranes for Fuel Cells” which describes that optimum methanol
concentration for direct methanol fuel cells (DMFCs) is 1-2 M, and that
methanol concentrations of 2 M or less are used in DMFCs due to a problem
of crossover of methanol through the electrolyte membrane. Reply Br. 2.
We note that the burden of establishing unexpected results rests
squarely upon the party asserting them. In re Klosak, 455 F.2d 1077, 1080
(CCPA 1972). This includes the burden of providing evidence that is
commensurate in scope with the claims. See In re Grasselli, 713 F.2d 731,
743 (Fed. Cir. 1983); In re Clemens, 622 F.2d 1029, 1035 (CCPA 1980).
See also In re Harris, 409 F.3d 1339, 1344 (Fed. Cir. 2005) (Evidence of
secondary considerations must be “commensurate in scope with the degree
of protection sought by the claimed subject matter.”)
Appellants’ evidence of unexpected results is not commensurate with
claim 1. Claim 1 does not require the liquid fuel be a methanol solution, nor
does it recite any concentration of methanol solution. While dependent
claim 19 requires the liquid fuel is a methanol solution, the methanol
concentration is 0.5 to 20 M, which includes the 1.3 M methanol solution
exemplified by Nakamura. Nakamura, 5:53-54 and 7:34. Further, claim 1
recites the carbonaceous porous body comprises amorphous carbon or a
composite of amorphous carbon and carbon material powder. Thus,
amorphous carbon can be present in any amount ranging from small
amounts up to 100% amorphous carbon. Appellants fail to explain how the
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porous bodies used in Examples 1 and 2 of the Specification are
representative of the entire range.

Claim 3
Claim 3 depends from claim 1 and further requires the carbonaceous
porous body has an average pore diameter of 1 to 100 µm and a porosity of
10 to 85%, and has a liquid-impregnating property given by a capillary
phenomenon. Appellants argue that column 6, lines 15-16 of Nakamura
cited by the Examiner concerns properties of Nakamura’s carbon plate (10)
prior to impregnation with platinum. App. Br. 7.
However, the Examiner finds Nakamura’s carbon plate has a porosity
between 30% to 60%, the aqueous metal solutions have a concentration of
40 g/l platinum and 0.56 g/l tin, and the average pore diameter is 10 µm.
Ans. 14, referring to Nakamura 3:42, 5:10, 22 and 6:15-16. The Examiner
finds that “[c]onsidering the diluteness of the metal solutions and the
broadness of [Appellants’] claimed range of 10 to 85% porosity and pore
diameter of 1 to 100 [µm] (in claim 3), it is noted that Nakamura meets the
liquid-impregnating property as claimed.” Ans. 14. Appellants fail to rebut
these findings, and therefore fail to identify harmful error in the Examiner’s
rejection of claim 3.

Claim 9
Claim 9 depends from claim 1 and further requires “the carbonaceous
porous body has a though hole for degassing and accelerating impregnation
of liquid fuel in an inside thereof, the through hole having no capillary force
and being distinct from pores of the carbonaceous porous body.” Appellants
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argue that Nakamura discloses the function of the through holes during
production of the electrode, not during impregnation of liquid fuel. App. Br.
7-8. We disagree. The Examiner finds Nakamura teaches the function of
the through holes during use in a fuel cell, specifically, carbon monoxide gas
formed by the electrode reaction flows out of the electrode by way of the
through holes. Ans. 15. In other words, Nakamura’s through holes provide
for degassing as herein claimed. The Examiner also finds “there is no
capillary force in the through-holes [of Nakamura] because the carbon
monoxide formed by the electrode reaction during use smoothly flows out of
the electrode.” Id. Appellants fail to rebut this finding.

Claim 11
Claim 11 depends from claim 1 and further requires “a partition wall
for controlling absorption of the liquid fuel or diffusion of the air is provided
opposite to the back side of the surface having the electrode layer in the unit
cell.” Appellants argue that the Examiner does not explain how Nakamura
discloses a unit cell having a back side of a surface having an electrode
layer. App. Br. 8. Moreover, Appellants argue that Ren fails to disclose a
partition wall that controls absorption of liquid fuel or diffusion of air. Id.
Appellants’ arguments are unpersuasive. The Examiner finds
Nakamura’s platinum is the anode and the carbonaceous porous material is
the base material. Supp. Ans. 5. As seen in Nakamura’s Figure 6, the front
surface and through holes of carbon plate (10) are coated with platinum, but
the back surface (14) is uncoated. Nakamura, Fig. 6, and 6:26-52. Thus,
Nakamura’s back surface (14) corresponds to the back side of a surface
having an electrode layer. Further, the Examiner finds Ren teaches a fuel
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cell casing (10) that houses electrode/electrolyte/electrode layers of a fuel
cell. Supp. Ans. 7-8. The Examiner concludes it would have been obvious
to one of ordinary skill in the art to put the fuel cell of Nakamura in a
housing, as taught by Ren, for the benefit of protecting the fuel cell of
Nakamura. Id. at 8. The Examiner also finds that when the fuel cell of
Nakamura is enclosed in a casing, it functions to control the absorption of
the liquid fuel and diffusion of the air because the fuel cell is protected from
the external environment. Id. We note Appellants broadly disclose a
partition wall enclosing the space within which the methanol fuel resides.
Figure 4(b), numeral 19, and Spec., 24:18-22. Specifically, Appellants
disclose:
The above partition wall 19 [in Fig. 4(b)] shall not specifically be
restricted as long as it can cut off fuel or air, and it can be constituted
from, for example, a plastic plate, a metal plate, a glass plate and a
ceramic plate.

Id. Based on this broad description of the structure and function of a
partition wall, it is reasonable to interpret Ren’s casing as providing a
partition wall. Appellants fail to distinguish the claimed partition wall from
that provided by Ren.
CONCLUSION
Based on our consideration of the totality of the record before us, we
have weighed the evidence of obviousness found in the applied prior art with
Appellants’ countervailing arguments and evidence for nonobviousness and
conclude, by a preponderance of the evidence and weight of argument, that
the claimed invention encompassed by the appealed claims would have been
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obvious as a matter of law under 35 U.S.C. § 103(a). Accordingly, the § 103
rejections of claims 1, 3, 7, 9, 11, 13, 15, 17 and 19 are affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).

AFFIRMED

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