PTAB

IPR2018-00783

Amperex Technology Ltd v. LG Chem Ltd

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Organic/Inorganic Composite Separator
  • Brief Description: The ’241 patent discloses an organic/inorganic composite separator for electrochemical devices, such as lithium-ion batteries. The separator includes a porous substrate coated with a porous active layer, which contains a mixture of inorganic particles and a binder polymer.

3. Grounds for Unpatentability

Ground 1: Obviousness over Bucci - Claims 1-5, 9-10, and 24-29 are obvious over Bucci.

  • Prior Art Relied Upon: Bucci (UK Patent Application No. GB 2 005 289 A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Bucci taught all elements of the challenged claims. Bucci disclosed a composite inorganic/organic separator for secondary batteries, comprising a porous substrate ("fabric material") coated with a porous active layer. This layer contained inorganic particles (e.g., kaolin) dispersed in a binder polymer (e.g., styrene-butadiene copolymer, SBR). Crucially, Petitioner asserted that Bucci taught the "heterogeneity" limitation of claim 1 by disclosing a two-step coating process. An "initial coating" had a 50:50 ratio of kaolin to SBR, while the "second coating" applied on top had a 45:55 ratio, meaning the surface region had a higher content of binder polymer than the inside region.
    • Motivation to Combine: Not applicable (single reference ground).
    • Expectation of Success: Not applicable (single reference ground).

Ground 2: Obviousness over Bucci in view of Yong - Claims 11-12, 14-23, 30-31, and 33-36 are obvious over Bucci in view of Yong.

  • Prior Art Relied Upon: Bucci (UK Patent Application No. GB 2 005 289 A) and Yong (WO 2005/076388).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon Bucci's separator structure by incorporating specific binder polymers taught by Yong. Petitioner argued that Yong disclosed binder polymers containing functional groups recited in claims 11 and 12, such as cyanoethylpolyvinylalcohol (CEPVA), which contains both hydroxy and cyano groups. Yong also taught using mixtures of polymers, including those with specific solubility parameters and functional groups (e.g., halogen, acetate) that mapped to other dependent claims. Petitioner contended that substituting or adding Yong's taught polymers into Bucci's general separator framework rendered the claims obvious. The method claims (e.g., 30, 31, 33) were argued to be obvious by applying the binder polymers from Yong within the manufacturing process disclosed by Bucci.
    • Motivation to Combine: A POSITA would combine the teachings to improve the separator disclosed in Bucci. Petitioner argued that Yong explicitly taught that hydrophilic polymers like CEPVA are desirable because they improve bonding with inorganic particles and enhance electrolyte retention—known goals in separator design. A POSITA would therefore have been motivated to use the specific hydrophilic polymers from Yong in the composite separator of Bucci to achieve these predictable benefits.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because both references addressed composite battery separators. The binder polymer in Yong served the same function as in Bucci—to interconnect and fix inorganic particles—making it compatible and its incorporation straightforward.

Ground 3: Obviousness over Hennige - Claims 1-5, 9-10, and 24-39 are obvious over Hennige.

  • Prior Art Relied Upon: Hennige (WO 2004/021499).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hennige alone taught all elements of the challenged claims. Hennige disclosed an electrical separator comprising a porous nonwoven substrate with a porous inorganic coating containing oxide particles (e.g., Al2O3) and an "adherence agent" (organofunctional silanes) that polymerizes to act as a binder. Petitioner asserted that Hennige also taught the "heterogeneity" limitation by disclosing the application of a second layer of "shutoff particles," such as a polyolefin polymer, on top of the initial inorganic coating. This resulted in a structure where the surface region (the polyolefin shutoff layer) contained more binder polymer than the inside region (the silane-based adherence agent mixed with inorganic particles).
    • Motivation to Combine: Not applicable (single reference ground).
    • Expectation of Success: Not applicable (single reference ground).

4. Key Claim Construction Positions

  • "active layer": Petitioner proposed this term be construed as a "layer containing a mixture of inorganic particles and binder polymer." This construction defined the scope of the coated layer central to the patent's claims.
  • "heterogeneity of composition morphology toward a thickness direction...": Petitioner proposed this lengthy phrase be construed to mean "the content ratio of binder polymer/inorganic particles present in a surface of a porous active layer is higher than that of binder polymer/inorganic particles present beneath (inside) the surface of the porous active layer." This construction was critical to Petitioner's obviousness arguments, as it defined the specific polymer gradient that Petitioner argued was disclosed in the prior art references Bucci and Hennige.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-5, 9-12, 14-31, and 33-36 of the ’241 patent as unpatentable.