Appeal No. 2006-2101
Application No. 10/085,303
batteries. Also, Boryta teaches producing battery grade lithium
containing less than 100 ppm sodium as an impurity (see
paragraph 0022). Accordingly, based on the teachings of
Harrison and Boryta, we fully concur with the examiner that it
would have been obvious for one of ordinary skill in the art to
prepare a lithium electrochemical cell containing no sodium
impurity or at the low levels of concentrations claimed.
Appellants' principal contention is that neither Harrison
nor Boryta teaches low sodium concentrations throughout the
lithium cell, i.e., the references do "not suggest paying
special attention to the overall sodium content of a lithium
cell, which includes not only the electrode including lithium as
the active metal but also, for example, the electrolyte, the
container, the current collectors, the separators, and any tape
and other components" (page 11 of principal brief, penultimate
paragraph). However, we agree with the examiner that one of
ordinary skill in the art would not have read Harrison and
Boryta as narrowly as proposed by appellants but, rather, would
have understood that the presence of sodium throughout the
entirety of the cell would be problematic for the lithium
electrodes. It stands to reason that if it was known that
sodium is a harmful impurity for lithium electrodes, one would
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