PTAB

IPR2020-01589

Amprius Inc v. CF Traverse LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Energy Storage Devices
  • Brief Description: The ’017 patent describes energy storage systems, such as lithium-ion batteries, wherein an electrode substrate includes nanofibers. The nanofiber substrate is coated with an intercalation material configured to reversibly adsorb charge carriers to improve battery capacity and performance.

3. Grounds for Unpatentability

Ground 1: Obviousness over Taberna - Claim 11 is obvious over Taberna

  • Prior Art Relied Upon: Taberna et al., "High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery appliactions," Nature Materials 5 (July 2006) (“Taberna”).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Taberna, a single reference, discloses every element of independent claim 11. Taberna describes creating and testing coin-type battery cells that constitute an "energy storage system." These cells include a positive electrode, a negative electrode (Li metal), and a separator (glass-fibre sheet) saturated in electrolyte, establishing the basic system structure. Petitioner asserted that Taberna’s "copper nanopillar-Fe3O4 assembly" on a copper foil substrate meets the limitation of "a substrate including nanofibers." The core of this argument was that the copper nanorods (nanopillars) grown on the copper foil form a unitary structure that functions as the claimed substrate. The subsequent coating of these nanorods with polycrystalline iron oxide (Fe3O4) was argued to meet the limitation of "an ion material attached to the substrate, the ion adsorbing material including a 3d metal oxide," as Fe3O4 is an oxide of iron, a first-row transition (3d) metal, and is shown to react with lithium ions.
    • Motivation to Combine: Not applicable for a single-reference ground. Petitioner contended that a person of ordinary skill in the art (POSA) would have recognized that Taberna's disclosed electrode architecture, designed for and tested in lithium-ion batteries, rendered the configuration of claim 11 obvious.
    • Expectation of Success: Not explicitly separated from the primary mapping argument. The success was demonstrated by Taberna itself, which reported that its nano-architectured electrodes provided excellent rate capability and capacity retention, confirming their function as effective energy storage devices.

Ground 2: Obviousness over Taberna and Arita - Claim 12 is obvious over Taberna in view of Arita

  • Prior Art Relied Upon: Taberna and Arita (Japanese Patent Application Publication No. 2007-188877).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground challenged dependent claim 12, which adds the limitation that "the ion adsorbing material includes silicon." Petitioner asserted that Taberna teaches the base energy storage system of claim 11, as detailed in Ground 1. Arita was introduced to supply the teaching of including silicon in the ion adsorbing material. Arita discloses a rechargeable battery electrode where an active material, preferably silicon due to its "large discharge capacity," is formed on nanofibers. Petitioner argued that it would have been obvious to supplement Taberna’s Fe3O4 coating with silicon as taught by Arita.
    • Motivation to Combine: A POSA would combine Taberna and Arita to improve the overall capacity and performance of the battery. Taberna teaches a high-performance nanostructured electrode, and Arita teaches that silicon is a highly desirable material for increasing battery capacity. Therefore, a POSA would have been motivated to incorporate Arita’s high-capacity silicon into Taberna’s high-performance electrode structure to achieve a battery with both superior capacity and excellent cycling stability.
    • Expectation of Success: A POSA would have had a reasonable expectation of success. While silicon was known to have issues with volumetric expansion during lithiation, Arita explicitly teaches methods to overcome this challenge. Arita discloses electrode structures with gaps or spacing to accommodate silicon's expansion without detachment from the current collector. Petitioner argued a POSA would recognize that combining Arita's silicon with Taberna's nanorod architecture—which inherently provides space between the rods—would predictably accommodate such expansion, leading to a battery with improved cycling characteristics and high capacity.

4. Key Claim Construction Positions

  • "3d metal oxide" (claim 11): Petitioner proposed this term be construed to mean "an oxide of a first-row transition metal." This construction was central to Ground 1, as it allowed the iron oxide (Fe3O4) disclosed in Taberna to meet the claim limitation. Petitioner supported this construction by citing the patent specification, which lists examples of transition metal oxides, and external technical articles that consistently define "3d metals" as the first row of transition metals on the periodic table (e.g., Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn).

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under 35 U.S.C. §325(d) or §314(a).
  • §325(d): The petition asserted that denial was improper because the primary prior art references, Taberna and Arita, were not considered by the examiner during the original prosecution of the ’017 patent.
  • §314(a) (Fintiv Factors): Petitioner argued against denial based on a parallel district court litigation (CF Traverse LLC v. Amprius, Inc.). The petition contended that the litigation was in a very early stage, with a Markman hearing scheduled but no trial date set and minimal discovery having occurred. Therefore, instituting the inter partes review (IPR) would not be an inefficient use of resources and would align with the strong merits of the invalidity grounds presented.

6. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 11 and 12 of the ’017 patent as unpatentable under 35 U.S.C. §103.