Amperex Technology Ltd v. Maxell Ltd

1. Case Identification

• Case #: IPR2021-01443
• Patent #: 9,350,019
• Filed: September 23, 2021
• Petitioner(s): Amperex Technology Limited
• Patent Owner(s): Maxell Holdings, Ltd.
• Challenged Claims: 1-5

2. Patent Overview

• Title: Nonaqueous Secondary Battery
• Brief Description: The ’019 patent discloses a nonaqueous secondary battery featuring a positive electrode with an active material density of at least 3.5 g/cm³. The active material comprises at least two lithium-containing transition metal oxides with different average particle sizes, combined with a negative electrode and a nonaqueous electrolyte containing a compound with at least two nitrile groups.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are obvious over Choi in view of Kim

• Prior Art Relied Upon: Choi (Chinese Patent Publication No. CN1822414) and Kim (Application # 2005/0208371).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Choi taught all elements of the claimed battery except for the dinitrile compound in the electrolyte. Choi disclosed a lithium secondary battery with at least two positive electrode active materials of different particle sizes, a positive electrode mixture layer with a density of 3.2 to 4.0 g/cm³, a negative electrode, and a nonaqueous electrolyte. Petitioner contended that the specific chemical formulas and elemental ranges for the lithium-containing transition metal oxides recited in claims 1, 2, and 5 were disclosed or rendered obvious by Choi, which taught overlapping or subsuming ranges for the constituent elements (e.g., Li, Co, Ni, Mg). Kim was cited for its teaching of adding an aliphatic nitrile compound (including compounds with two nitrile groups) to the electrolyte of a similar lithium secondary battery.
  • Motivation to Combine: Petitioner asserted a POSITA would combine the references to improve the thermal stability of the battery disclosed in Choi. Choi’s stated goal was improving thermal stability and discharge characteristics. Kim explicitly taught that incorporating a dinitrile compound into the electrolyte forms a protective layer on the positive electrode, which improves thermal stability and prevents thermal runaway—a known problem in the art that Choi sought to solve. The combination would have been a simple and predictable substitution of Choi’s electrolyte with Kim’s enhanced electrolyte.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because both references described similar battery components (cathode, anode, electrolyte materials) and pursued the common goal of improving battery performance and stability. The underlying lithium-ion chemistry was predictable, and Kim explicitly explained the benefits of its dinitrile additive.

Ground 2: Claims 1-5 are obvious over Koshiishi in view of Abe

• Prior Art Relied Upon: Koshiishi (Chinese Patent Publication No. CN1848492) and Abe (Application # 2004/0013946).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Koshiishi taught a lithium-ion secondary battery containing all major components of the claimed invention, again with the exception of the dinitrile compound. Koshiishi disclosed a positive electrode with at least two lithium-containing transition metal oxides having different average particle sizes (e.g., 13 µm and 10 µm), a density of at least 3.7 g/cm³, a negative electrode, and a nonaqueous electrolyte. Petitioner asserted that Koshiishi’s specific oxide formulas (Compound A and Compound B) disclosed or suggested the elemental compositions and ranges required by the claims. Abe was introduced for its disclosure of adding a dinitrile compound to a non-aqueous electrolyte to improve battery performance.
  • Motivation to Combine: The primary motivation asserted was to improve the battery capacity of Koshiishi, a major driver of development in the field. Koshiishi identified improving capacity as a goal for its battery. Abe taught that adding a dinitrile compound to its electrolyte improves discharge capacity retention by preventing oxidative decomposition at the cathode. A POSITA seeking to enhance the capacity of Koshiishi’s battery would have looked to known solutions like the dinitrile additive in Abe.
  • Expectation of Success: Success was expected because both references related to similar lithium-ion battery technology and shared the objective of increasing capacity. The combination involved substituting the electrolyte in Koshiishi with the known, capacity-improving electrolyte from Abe, a modification within the predictable skill of a POSITA.

4. Key Claim Construction Positions

• "Different compositions of elements" (Claim 3) / "composition of elements...is different" (Claim 4): Petitioner contended that these terms should be given their plain and ordinary meaning, which encompasses either the use of different elements or different amounts of the same elements between the at least two lithium-containing transition metal oxides. This construction was argued to be supported by the patent’s specification and was critical to the obviousness arguments, as the prior art references disclosed oxide pairings with different elemental ratios, thereby meeting the limitation under this interpretation.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) based on the Fintiv factors would be inappropriate. The core arguments were that the co-pending district court litigation was in its infancy, with jurisdictional disputes unresolved and no trial date set. Investment in the district court proceedings had been minimal, discovery was stayed, and invalidity contentions were not yet due in one of the parallel cases. Petitioner further asserted that the grounds presented in the IPR were particularly strong and had not been previously considered by the USPTO, weighing heavily in favor of institution.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-5 of the ’019 patent as unpatentable.