Guangdong MIC Power New Energy Co Ltd v. VARTA Microbattery GmbH

1. Case Identification

• Case #: IPR2021-01207
• Patent #: 10,804,506
• Filed: June 30, 2021
• Petitioner(s): Guangdong Mic-Power New Energy Co. Ltd., PEAG LLC d/b/a JLab Audio, Audio Partnership LLC, Audio Partnership PLC d/b/a Cambridge Audio, GN Audio A/S and GN Audio USA Inc. d/b/a Jabra
• Patent Owner(s): VARTA Microbattery GmbH
• Challenged Claims: 1-20

2. Patent Overview

• Title: Rechargeable Button Cell
• Brief Description: The ’506 patent discloses a rechargeable button cell containing a spiral wound electrode-separator assembly. The design features include two metal housing halves separated by a seal, an internal winding with a coreless open cavity, and metal foil conductors welded to the electrodes and housing to serve as electrical contacts.

3. Grounds for Unpatentability

Ground 1: Obviousness over Kannou and Kawamura - Claims 1-9 and 11-19 are obvious over Kannou in view of Kawamura.

• Prior Art Relied Upon: Kannou (Japanese Patent Publication No. 2003-31266) and Kawamura (Application # 2007/0218356).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kannou teaches all fundamental elements of the challenged claims, including a rechargeable button cell with a wound electrode assembly, a coreless open cavity, and metal housing halves with planar regions. Kannou’s metal tabs function as the claimed metal foil conductors. Kawamura was argued to supply the teachings of welding these conductors to the housing and using an insulating plate between the winding and the housing. For example, claim 1’s requirement for metal foils attached by a weld was allegedly met by combining Kannou’s tabs with Kawamura’s teaching of spot-welding electrode leads to the housing halves.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these references to improve the button cell of Kannou. A POSA would incorporate the spot-welding from Kawamura to ensure the tabs in Kannou maintain stable contact with the housing, thereby improving electrical connectivity. Furthermore, since Kannou identified a risk of internal short circuits, a POSA would be motivated to add the insulating plate taught by Kawamura to isolate the electrode assembly and reduce this risk.
  • Expectation of Success: Petitioner asserted a high expectation of success, as the combination involved applying a known technique (welding) and a standard component (insulator) to a known device (Kannou's button cell) to achieve the predictable results of improved reliability and safety.

Ground 2: Obviousness over Kannou, Kawamura, and Kaun - Claims 10 and 20 are obvious over Kannou in view of Kawamura and Kaun.

• Prior Art Relied Upon: Kannou, Kawamura, and Kaun (Application # 2005/0233212).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds on the Kannou/Kawamura combination and adds Kaun to address the limitations of claims 10 and 20, which recite that "the edge of the second housing half is not crimped over an edge of the first housing half." Petitioner asserted that while Kannou discloses crimping its housing halves together, Kaun explicitly teaches an improved button cell housing that is closed to provide a liquid-tight seal without crimping. Kaun achieves this seal using an insert-molded gasket between the housing top and cup.
  • Motivation to Combine: Kannou acknowledged a problem of "wasted space" in conventional button cells, a problem exacerbated by crimping. A POSA would be motivated to replace Kannou’s crimped seal with the non-crimped sealing mechanism from Kaun to increase the effective internal volume, allowing for higher battery capacity. This modification would also prevent potential damage to sealing members or other components caused by the crimping process.
  • Expectation of Success: The expectation of success was argued to be high because it involved substituting one known sealing method for another to achieve the known benefits of improved volumetric efficiency and reduced risk of damage.

Ground 3: Obviousness over Kannou, Kawamura, and Kubota - Claims 1-9 and 11-19 are obvious over Kannou in view of Kawamura and Kubota.

• Prior Art Relied Upon: Kannou, Kawamura, and Kubota (Patent 5,654,114).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground adds Kubota to the primary combination to provide explicit teachings for dependent claims related to insulation. Specifically, claims 2 and 12 require an "insulating tape adhesively bonded" to a conductor, and claims 9 and 19 require the winding's outer side be "protected by an insulating film." Petitioner argued that Kubota discloses an insulating friction tape adhered to lead tabs and an insulating end tape adhered to the outside of the rolled electrode body, directly corresponding to these limitations.
  • Motivation to Combine: A POSA, aware of the short-circuit risk identified in Kannou, would be motivated to incorporate the specific tape-based insulation methods from Kubota into the Kannou/Kawamura cell. Kubota’s tapes offer an inexpensive and compact way to further enhance insulation between the conductors and the winding, and to secure the winding from unwinding, thereby predictably reducing short-circuit risk.
  • Expectation of Success: High, as adding insulating tapes is a common and routine practice in battery manufacturing to improve safety and structural integrity.
• Additional Grounds: Petitioner asserted additional obviousness challenges against claims 1-9 and 11-19 based on Kannou, Kawamura, and Myerberg, and against claims 10 and 20 based on Kannou, Kawamura, Myerberg, and Kaun. These grounds relied on similar modification theories, with Myerberg providing further teachings on volumetrically efficient folded tabs and insulation discs.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise discretionary denial under §314(a) based on Fintiv factors. It was noted that one of four parallel district court cases was already stayed and motions to stay were pending in the others. Petitioner contended that the court proceedings were in their infancy, with minimal investment from the parties or the court, and that different invalidity arguments would be raised in the district court action.
• Petitioner also argued against denial under §325(d), asserting that the primary prior art references (Kannou and Kaun) were not substantively examined during prosecution. Although cited in a large Information Disclosure Statement (IDS), there was no evidence the Examiner considered their specific teachings. Petitioner contended this failure to appreciate the art was a material error, as the references disclose nearly all key claim limitations.

5. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 1-20 of the ’506 patent as unpatentable under 35 U.S.C. §103.