Ex Parte Hamamoto et al

Board of Patent Appeals and Interferences

Oct 13, 2009

10383790 (B.P.A.I. Oct. 13, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte TOSHIKAZU HAMAMOTO, KOJI ABE, TSUTOMU TAKAI,
and YASUO MATSUMORI
____________

Appeal 2009-006777
Application 10/383,790
Technology Center 1700
____________

Decided: October 13, 2009
____________

Before EDWARD C. KIMLIN, BRADLEY R. GARRIS, and
CHARLES F. WARREN, Administrative Patent Judges.

GARRIS, Administrative Patent Judge.

DECISION ON APPEAL

Appellants appeal under 35 U.S.C. § 134 from the Examiner’s
decision rejecting claims 7-15. We have jurisdiction under 35 U.S.C. § 6.
We REVERSE.
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Statement of the Case
Appellants claim a non-aqueous electrolytic solution comprising an
electrolyte dissolved in a non-aqueous solvent comprising a combination of
a cyclic carbonate and a linear carbonate in a particular ratio and which
contains a disulfide derivative having the formula R1-S-S-R2 such as
diphenyl disulfide (claim 13). Appellants also claim a non-aqueous
secondary battery comprising the above described electrolytic solution
(claim 7). According to Appellants, the claimed disulfide derivative
increases the discharge capacity retention of a non-aqueous secondary
battery (Spec. 2-4).
Appellants’ claimed invention is adequately represented by
independent claim 13 which reads as follows:
13. A non-aqueous electrolytic solution comprising an
electrolyte dissolved in a non-aqueous solvent comprising a
combination of a cyclic carbonate and a linear carbonate,
wherein the ratio of cyclic carbonate to linear carbonate ranges
from 1:4 to 7:3 and which contains a disulfide derivative having
the following formula:

R1-S-S-R2

wherein each of R1 and R2 independently represents a phenyl
group, a benzyl group, a tolyl group, a pyridyl group, a
pyrimidyl group, an alkyl group having 1 to 12 carbon
atom, or a cycloalkyl group having 3 to 6 carbon atoms,
provided that each group may have one or more substituent
groups in an amount of 0.02 to 0.9 weight %.

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The references set forth below are relied upon by the Examiner as
evidence of obviousness:
Yoshimitsu 4,888,255 Dec. 19, 1989
Mikiya JP 07320779 Dec. 08, 1995
(JP ‘779; Mikiya Yamazaki)1

The Examiner rejects all appealed claims under 35 U.S.C. § 103(a) as
being upatentable over JP ‘779 in view of Yoshimitsu.
The Examiner’s obviousness conclusion is expressed as follows:
It would have been obvious to one of ordinary skill in the art at
the time the invention was made to provide an organic disulfide
compound having the claimed R-groups, including diphenyl
disulfide, [as taught in Yoshimitsu] to the electrolyte used in a
lithium secondary battery as described in the Mikiya (JP 07-
320,779) reference in order to enhance the storing and
charge/discharge characteristics of the battery, as similar
disulfides are used to enhance storing and charge/discharge
characteristics in the lithium batteries of Mikiya. One of
ordinary skill in the art would recognize that the disulfides
taught in Yoshimitsu provide the same properties, including
improved discharge characteristics, to the electrolyte as desired
by Mikiya, which uses similar sulfide compounds for the same
reasons (see MPEP 2144.06 which states that substituting
equivalents known for the same purpose is obvious.) (Ans. 4).
Issue
Have Appellants shown error in the Examiner’s conclusion that it
would have been obvious to provide the electrolytic solution of JP ‘779 with
the diphenyl disulfide of Yoshimitsu?

1 Our understanding of this reference is based on the translation of record dated January 2009.
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Findings of Fact
JP ‘779 discloses a non-aqueous electrolytic solution of the type
generally defined by claim 13 and which contains a sulfide for suppressing
decomposition of the electrolyte (para. [0016]). The Examiner
acknowledges that the sulfides of JP ‘779 do not include the disulfide
derivatives such as diphenyl disulfide claimed by Appellants (Ans. para.
bridging 3-4).
Yoshimitsu discloses a non-aqueous electrochemical cell comprising
an alkali metal anode and liquid oxyhalide as a cathode-electrolyte (col. 1, ll.
4-43). Yoshimitsu teaches:
[T]he alkali metal in the anode and the oxyhalide in the
electrolyte are in direct contact so that an alkali metal halide is
produced from the reaction between them to form a film on the
surface of the anode. This film of the alkali metal halide is
rough and course initially but develops during the storage at
elevated temperatures for over a long period of time to be tight
and dense, whereby the anode is inactivated.
(Id. at ll. 24-32).

Yoshimitsu avoids this inactivation problem by incorporating into the
electrolyte an aromatic compound which keeps the alkali halide formed on
the anode rough and course (col. 1, l. 63 - col. 2, l. 11). Yoshimitsu
discloses many aromatic compounds which perform this function (col. 4, ll.
13-47), one of which is diphenyl disulfide (id. at l. 17).
These findings are not disputed in the record of this appeal.
Principles of Law
“Rejections on obviousness grounds cannot be sustained by mere
conclusory statements; instead, there must be some articulated reasoning
with some rational underpinning to support the legal conclusion of
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obviousness.” In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006), cited with
approval in KSR Int’l. Co. v. Teleflex Inc., 550 U.S. 398, 417-18 (2007).
Analysis
Appellants present the following argument in support of their non-
obviousness position:
It is thus clear that the invention of JP '779 and that disclosed in
Yoshimitsu, et al. '255 differ in several significant ways. In
particular,

1. JP '779 uses an organic solvent for the electrolyte while SR
[sic, Yoshimitsu] uses an inorganic solvent (an oxyhalide);

2. The additive in JP '779 is for the purpose of maintaining the
organic solvent from decomposition degradation. In contrast,
the additive in Yoshimitsu '255 is for the purpose of
maintaining the rough and coarse alkali metal halide film from
becoming tighter and more dense; and

3. The incorporation of the additive of JP '779 improves the
charge-and-discharge cycle property whereas the incorporation
of the additive in Yoshimitsu, et al. '255 reduces the voltage
drop at the initial stage of discharge.

Thus, because of these significant difference[s], one skilled in
the art would not be inclined or motivated in any way to
combine these disclosures. They are mutually exclusive and
the skilled artisan would have no reason to attempt to combine
these disclosures in the manner attempted by the Examiner.
(App. Br. 7).

The Examiner provides the following response to Appellants’
argument:
Appellant chooses to ignore the clear similarities found in the
teachings of the references. First, both references are to lithium
batteries that employ lithium as the active material and lithium
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based electrolytes which are taught to include carbonates.
Second, both references teach disulfide compounds as additives
in the electrolytes of the batteries to improve the discharge
characteristics of the batteries (see Mikiya, paragraphs 13-
18 and Yoshimitsu, col. 15, lines 1-15; col. 1, lines 1-5.)
Further, Mikiya teaches that the sulfide used as an electrolyte
additive has the function of controlling decomposition
degradation of the electrolyte when the positive electrode has a
high potential (paragraph 13.) From this disclosure,
one skilled in the art would be motivated to use the additive to
prevent decomposition of the electrolyte and improve the
discharge characteristics of the battery. (Ans. 11).

The deficiency of the Examiner’s response is that it fails to
specifically rebut Appellants’ point that the sulphur-based additives of JP
‘779 and Yoshimitsu perform disparate functions. The sulfides of JP ‘779
suppress electrolyte decomposition. In contrast, the diphenyl disulfide of
Yoshimitsu prevents anode inactivation in an electrochemical cell that
contains an alkali metal anode and a liquid oxyhalide electrolyte wherein
these reactants form a halide metal film on the anode. In particular, the
diphenyl disulfide of Yoshimitsu is effective in keeping this film rough and
course so as to avoid voltage drop due to anode inactivation.
On this record, it is undisputed that the electrolyte of JP ‘779 does not
include an oxyhalide and therefore would not exhibit the alkali metal halide
film problems addressed by the diphenyl disulfide of Yoshimitsu.
Correspondently, it is undisputed that Yoshimitsu contains no teaching or
suggestion that diphenyl disulfide is capable of suppressing electrolyte
decomposition as desired by JP ‘779. These circumstances lead to a
determination that the Examiner has failed to provide articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness.
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Conclusions of Law
Appellants have shown error in the Examiner’s conclusion that it
would have been obvious to provide the electrolytic solution of JP ‘779 with
the diphenyl disulfide of Yoshimitsu.
For this reason, we cannot sustain the Examiner’s § 103 rejection of
all appealed claims as being unpatentable over JP ‘779 in view of
Yoshimitsu.
Order

The decision of the Examiner is reversed.

REVERSED

kmm

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