Amperex Technology Ltd v. Maxell Ltd

1. Case Identification

• Case #: IPR2021-01440
• Patent #: 8,691,446
• 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 ’446 patent discloses a nonaqueous secondary battery with a positive electrode containing at least two distinct lithium-containing transition metal oxides. These oxides have different average particle sizes and different elemental compositions to enhance battery performance.

3. Grounds for Unpatentability

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

• Prior Art Relied Upon: Choi (CN1822414) and Kim (2005/0208371).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Choi taught all elements of the claimed battery except for the specific electrolyte composition. Choi disclosed a lithium secondary battery with a positive electrode containing at least two lithium-containing transition metal oxides of different particle sizes and compositions, a negative electrode, and a nonaqueous electrolyte. For the final element, Petitioner asserted that Kim taught the missing limitation: a nonaqueous electrolyte containing a compound with at least two nitrile groups (specifically, an aliphatic nitrile compound like succinonitrile) to form a protective layer on the positive electrode. Petitioner contended that combining Choi’s battery structure with Kim’s electrolyte renders the claims obvious.
  • Motivation to Combine: The primary motivation asserted was to improve the thermal stability and safety of Choi’s battery. Choi’s stated goals included improving thermal stability. Kim explicitly taught that adding an aliphatic nitrile compound to the electrolyte improves thermal stability and discharge characteristics by preventing thermal runaway. A person of ordinary skill in the art (POSITA) would therefore combine Kim's known solution with Choi’s battery to achieve this predictable improvement.
  • Expectation of Success: Petitioner argued a POSITA would have a high expectation of success because both references related to similar lithium-ion battery systems with comparable cathode, anode, and electrolyte materials. The proposed modification was a simple substitution of Choi’s electrolyte with Kim’s, a predictable combination in the well-understood field of lithium-ion chemistry.

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

• Prior Art Relied Upon: Koshiishi (CN1848492) and Abe (2004/0013946).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Koshiishi, like Choi in Ground 1, disclosed the core elements of the claimed nonaqueous secondary battery. This included a positive electrode with two different lithium-containing transition metal oxides (Compound A and Compound B) having different average particle sizes and compositions, a negative electrode, and a nonaqueous electrolyte. Koshiishi, however, did not teach an electrolyte containing a compound with at least two nitrile groups. Petitioner asserted that Abe supplied this missing element by disclosing a nonaqueous electrolyte containing a dinitrile compound to improve battery performance.
  • Motivation to Combine: The motivation to combine Koshiishi and Abe was to improve the battery’s capacity and discharge capacity retention. Koshiishi stated that improving capacity was a primary goal. Abe identified oxidative decomposition in similar batteries as a cause of decreased discharge capacity and taught that adding a dinitrile compound to the electrolyte improves discharge capacity retention. A POSITA would combine Abe's known solution with Koshiishi's battery to achieve the desired and predictable outcome of enhanced capacity.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because both references disclosed similar lithium-ion battery components and sought to solve the common problem of capacity degradation. The combination involved substituting Koshiishi's electrolyte with Abe’s improved electrolyte, and Petitioner argued the result would have been predictable given the similar chemistries.

4. Key Claim Construction Positions

• "Different compositions of elements" / "composition of elements...is different" (Claims 1-3): Petitioner contended these terms should be given their plain and ordinary meaning, which covers situations where the at least two lithium-containing transition metal oxides contain either different elements or simply different amounts of the same elements. Petitioner noted this construction was consistent with the patent specification and the Patent Owner's own interpretation in co-pending district court litigation.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) and the Fintiv factors would be inappropriate. The co-pending district court litigation was in its infancy, with jurisdictional motions unresolved and no trial date set. Petitioner asserted that investment in the court proceedings had been minimal, a stay was likely to be requested, and the strong merits of the obviousness challenges presented in the petition weighed heavily in favor of institution to promote efficiency and system integrity.

6. Relief Requested

• Petitioner requests the institution of an inter partes review and the cancellation of claims 1-5 of the ’446 patent as unpatentable.