No Contradiction ⇒ No Indefiniteness

by Dennis Crouch

The Federal Circuit recently issued a decision in Maxell, Ltd. v. Amperex Technology Limited, No. 2023-1194 (Fed. Cir. Mar. 6, 2024), reversing Judge Alan Albright’s finding that certain claims of Maxell’s patent covering rechargeable lithium-ion battery indefinite under 35 U.S.C. § 112, ¶ 2 (112(b)). U.S. Patent No. 9,077,035.

The case provides important cover for patent prosecutors who inelegantly add narrowed limitations from the dependent claims into the independent claims without rewriting or deleting the corresponding broader element descriptions already there.

The key issue on appeal was whether two limitations in claim 1 regarding the transition metal element M1 contradicted each other, rendering the claim indefinite. The first limitation, labeled [c] by the court, is a Markush group requiring requiring that “M1 represents at least one transition metal element selected from Co, Ni and Mn.” The second limitation, [f], requires that “the content of Co in the transition metal M1 of the formulae (1) and (2) is from 30% by mole to 100% by mole.”

The district court held that these two limitations were contradictory because limitation [c] suggested that cobalt was optional, while limitation [f] required cobalt to be present at 30-100% by mole.

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