On March 6, 2024, the U.S. Court of Appeal for the Federal Circuit revered Judge Albright’s indefiniteness determination finding that two limitations within the same claim – one narrower than the other – did not render the claim indefinite because it was possible to meet both limitations. Maxell, Ltd. v. Amperex Technology Limited, Case No. 23-1194 (Fed. Cir. Mar. 6, 2024) (Prost, Taranto, Chen, JJ.).

This case centered around U.S. Patent No. 9,077,035 directed to a rechargeable lithium-ion battery. Maxell owns the ‘035 Patent and filed a suit against Amperex alleging infringement. At issue specifically were two limitations in the independent claim that recited the variable M¹.

The ‘035 Patent recited:

…

1[c] wherein M¹ represents at least one transition metal element selected from Co, Ni and Mn, …

…

1[f] wherein the content of Co in the transition metal M¹ … is from 30% by mole to 100% by mole, …

After claim construction proceedings, Judge Albright, in Western District of Texas, found independent claim 1 indefinite because the claim limitations were contradictory. Specifically, the District Court found that when one limitation made the element Co optional but a second limitation made Co necessary, the limitations were “contradictory on [their] face.”

The Federal Circuit, however, found no contradiction. The Court determined that because it is possible for a transition metal element to meet both requirements, the two limitations of the ‘035 Patent are not contradictory. Federal Circuit has long maintained that a limitation must be read in the full context of the claim and in context of the prosecution history of the patent. See Salazar v. AT&T Mobility LLC, 64 F.4th 1311 (Fed. Cir. 2023); Hall v. Taylor, 332 F.2d 844 (CCPA 1964). With respect to the ‘035 Patent, the Court found that because the first limitation (broader limitation) making Co optional was in the original claims but the second limitation (narrower limitation) was added during prosecution to overcome prior art, rather than contradict the first limitation, the second limitation narrowed the first limitation. The prosecution of ‘035 Patent also provided context for the ordering of the limitations and the structure of the claims. The Court noted that, had the second limitation been in a dependent claim, it would not be a contradiction, so the second limitation’s recitation in the independent claim lead to the same conclusion.

Amperex attempted to argue that claim language to define M¹ was different than claim language to define a element M² in the same claim making it difficult for a POSITA uncertain about the scope of the claims. The Court, unpersuaded, held that the difference in claim language would not make a POSITA irremediably uncertain about the scope of the claims because the language defining M¹ is clear and a POSITA would not simply borrow the claim language defining M² for M¹ especially since M¹ and M² are different and contain different elements.

Practical Guidance:

1. If there are two requirements in a claim, and it is possible to meet both, there is no contradiction.
2. Different claim language formulation for different features of a claim is likely not relevant to indefiniteness unless a POSITA may be "irremediably uncertain" about the scope of the claimed feature.