DCT

1:20-cv-01568

VARTA Microbattery GmbH v. Audio Partnership LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:20-cv-01568, N.D. Ill., 03/03/2020
  • Venue Allegations: Venue is based on Defendant Audio Partnership LLC’s alleged regular and established place of business and retail store in the district, and on Defendant Audio Partnership PLC’s status as a foreign alien.
  • Core Dispute: Plaintiff alleges that Defendant’s Melomania 1 wireless earphones, which contain microbatteries supplied by a third party, infringe four patents related to the internal construction of button cell batteries.
  • Technical Context: The technology concerns the design of small, rechargeable button-style batteries, focusing on a spirally wound internal structure that orients electrodes perpendicularly to the flat battery surfaces to improve mechanical strength and power density.
  • Key Procedural History: Subsequent to the filing of this complaint, all four patents-in-suit were the subject of Inter Partes Review (IPR) proceedings before the Patent Trial and Appeal Board. In each instance, all originally issued claims asserted in this complaint were cancelled and replaced with new, narrower substitute claims. This procedural development fundamentally reshapes the dispute, as the legal viability of the case now depends on whether infringement can be proven under these amended claims.

Case Timeline

Date Event
2009-02-09 Earliest Priority Date for '835, '581, '913 Patents
2009-06-18 Earliest Priority Date for '858 Patent
2015-10-06 U.S. Patent No. 9,153,835 Issues
2016-11-15 U.S. Patent No. 9,496,581 Issues
2017-10-24 U.S. Patent No. 9,799,913 Issues
2017-10-24 U.S. Patent No. 9,799,858 Issues
2020-03-03 Complaint Filed
2020-07-07 IPRs Filed Against All Four Patents-in-Suit
2022-04-07 IPR Certificate Issued for '835 Patent
2022-04-11 IPR Certificate Issued for '581 Patent
2022-04-28 IPR Certificate Issued for '913 Patent
2022-05-03 IPR Certificate Issued for '858 Patent
2023-02-23 Second IPR Certificate Issued for '581 Patent

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,153,835 - "Button Cells and Method for Producing Same"

Issued October 6, 2015

The Invention Explained

  • Problem Addressed: The patent’s background describes issues with conventional button cells where electrodes are stacked flatly, parallel to the housing top and bottom. This configuration is susceptible to leaking under axial mechanical loads, particularly in rechargeable lithium-ion cells where electrodes physically change volume during charging and discharging cycles ('835 Patent, col. 2:21-28).
  • The Patented Solution: The invention reorients the internal components. It uses an electrode-separator assembly formed into a spiral winding, where the electrode layers are aligned "essentially at right angles to the flat bottom and top areas" of the battery housing ('835 Patent, Abstract; col. 2:51-54). This design converts potentially damaging axial forces into radial forces, which the cylindrical housing wall can better withstand, improving sealing characteristics ('835 Patent, col. 4:40-55). The patent also specifies that the cell is closed "without being beaded over," a departure from a traditional manufacturing technique ('835 Patent, Abstract).
  • Technical Importance: This architecture was intended to create more robust, reliable, and space-efficient microbatteries suitable for the growing market of wearable electronics (Compl. ¶13-14).

Key Claims at a Glance

  • The complaint asserts independent claim 1.
  • Essential elements of Claim 1 (as originally issued):
    • A housing cup and a housing top forming a housing with flat bottom and top areas.
    • An electrode-separator assembly within the housing.
    • An insulating means.
    • The electrode layers are aligned essentially at right angles to the flat bottom and top areas.
    • The button cell is closed without being beaded over.
    • The electrode-separator assembly is in the form of a spiral winding.
    • The insulating means is arranged between the end faces of the spiral winding and the housing.

U.S. Patent No. 9,496,581 - "Button Cells and Method for Producing Same"

Issued November 15, 2016

The Invention Explained

  • Problem Addressed: Like the parent '835 patent, this patent addresses the mechanical stress and sealing problems in rechargeable button cells with traditionally stacked electrodes ('581 Patent, col. 2:21-38).
  • The Patented Solution: The '581 Patent also employs a spirally wound electrode assembly with layers oriented at right angles to the flat housing surfaces ('581 Patent, col. 4:32-38). The key distinction in the asserted claim is the specific mechanism for electrical connection: one of the electrodes connects to the housing via an "output conductor comprising a foil resting flat between an end face of the spiral winding and the flat top or the flat bottom area" ('581 Patent, col. 12:3-12). This describes using a piece of foil, held in place by pressure, to establish the electrical path.
  • Technical Importance: This specific connection method provides a simple and effective means to draw current from the novel spirally wound core without requiring complex or space-consuming connection hardware (Compl. ¶18).

Key Claims at a Glance

  • The complaint asserts independent claim 1.
  • Essential elements of Claim 1 (as originally issued):
    • A housing cup and a housing top forming a housing with flat bottom and top areas.
    • An electrode-separator assembly with positive and negative electrodes.
    • The electrode layers are aligned essentially at right angles to the flat bottom and top areas.
    • The assembly is a spiral winding with end faces.
    • One electrode connects to the housing via an output conductor comprising a foil resting flat between an end face of the winding and the housing surface.

U.S. Patent No. 9,799,913 - "Button Cells and Method for Producing Same"

Issued October 24, 2017 (Multi-Patent Capsule)

Technology Synopsis

This patent discloses a button cell with the same right-angle spiral winding architecture as its sibling patents. Its claims combine features discussed separately in the other patents, requiring both an output conductor foil for electrical connection and a separate flat layer of plastic (an insulator) to prevent short circuits between the winding's end faces and the housing ('913 Patent, claim 1).

Asserted Claims

Claims 1, 4, and 6 (Independent Claim 1).

Accused Features

The complaint alleges the accused M1254S2 battery contains both a foil-based output connector and a plastic insulator layer, thereby meeting the combination of elements required by the '913 Patent (Compl. ¶64-66).

U.S. Patent No. 9,799,858 - "Button Cell having Winding Electrode and Method for the Production Thereof"

Issued October 24, 2017 (Multi-Patent Capsule)

Technology Synopsis

This patent also concerns button cells with spirally wound electrodes. It is distinguished by its focus on the method of connecting the electrodes to the housing, specifically claiming that a metal conductor connects to the housing half with "weld beads and/or weld spots passing through the housing" from the "outer side" ('858 Patent, Abstract; claim 1). This describes a laser welding process that creates a robust, permanent electrical bond.

Asserted Claims

Claim 1.

Accused Features

The complaint alleges the M1254S2 battery contains conductors connected to the housing via weld beads or spots that originate from the outside of the housing (Compl. ¶74, 76).

III. The Accused Instrumentality

Product Identification

The accused products are Cambridge Audio "Melomania 1" wireless earphones, which are alleged to contain infringing "M1254S2" microbatteries manufactured by "MIC-Power of China" (Compl. ¶27).

Functionality and Market Context

The M1254S2 batteries are the rechargeable power source for the earphones (Compl. ¶28). The complaint alleges these batteries embody the patented technology, featuring a housing with flat top and bottom areas and an internal, spirally wound electrode-separator assembly (Compl. ¶29-31). The complaint provides a visual representation comparing a photograph of the accused battery with a diagram of its alleged internal structure (Compl. p. 9). This diagram depicts concentric layers labeled "Electrode-Separator Assembly" inside a housing, consistent with the patent's teachings.

IV. Analysis of Infringement Allegations

'835 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a housing cup and a housing top separated from one another by an electrically insulating seal and which form a housing with a flat bottom area and a flat top area The M1254S2 batteries are alleged to have a housing cup and top with an insulating seal, forming a housing with a flat bottom and flat top. ¶36 col. 6:55-61
an electrode-separator assembly within the housing... with a positive and a negative electrode... connected to one another by a flat separator The accused batteries allegedly contain an electrode-separator assembly with positive and negative flat-layer electrodes connected by a separator. ¶37 col. 4:22-28
wherein the electrode layers are aligned essentially at right angles to the flat bottom area and the flat top area The electrode layers in the accused batteries are allegedly aligned at right angles to the flat housing areas. ¶38 col. 2:51-54
and the button cell is closed without being beaded over The housing of the accused batteries is allegedly closed without being beaded over. ¶38 col. 6:46-54
the electrode-separator assembly is in the form of a spiral winding having end faces... The assembly in the accused batteries is allegedly a spiral winding with end faces. ¶39 col. 4:62-65
wherein the insulating means is arranged between the end faces of the spiral winding and the housing cup and the housing top The accused batteries are alleged to have an insulator between the winding end faces and the housing. ¶40 col. 11:16-21

Identified Points of Contention

  • Scope Questions: The primary point of contention is procedural: the asserted claim 1 of the '835 Patent was cancelled during a post-filing IPR. The analysis will now depend on the scope of the new, narrower substitute claim 14, which adds limitations including that the cell is a "rechargeable lithium-ion" type and is held together by a "force-fitting connection" ('835 Patent, IPR Cert., col. 1:12-34). The court will have to determine if Plaintiff can amend its allegations to meet these new, more specific requirements.
  • Technical Questions: A factual question is whether the accused battery is in fact "closed without being beaded over." The precise manufacturing and sealing method used for the M1254S2 battery will be a central evidentiary issue.

'581 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a housing cup and a housing top separated from one another by an insulating seal and which form a housing with a flat bottom area and a flat top area The M1254S2 batteries are alleged to have this housing structure. ¶48 col. 12:15-19
an electrode-separator assembly... is a spiral winding having end faces defining side surfaces of the spiral winding facing in an axial direction... The accused batteries allegedly contain such a spirally wound assembly. ¶51 col. 12:25-30
one of the electrodes connects to the flat bottom area or the flat top area via an output conductor comprising a foil resting flat between an end face of the spiral winding and the flat top or the flat bottom area to which it is connected The accused batteries allegedly have an electrode connected to the housing via a foil that rests flat between the winding and the housing surface. ¶52 col. 12:31-37

Identified Points of Contention

  • Scope Questions: As with the '835 patent, the asserted claim 1 of the '581 Patent was cancelled in an IPR. The replacement substitute claim 14 requires the electrode connection to be made via a "weld" ('581 Patent, IPR Cert., col. 2:1-5). This raises the question of whether the Plaintiff’s allegation of a connection via a "foil resting flat" can meet the new, explicit "weld" requirement.
  • Technical Questions: A central issue will be the exact nature of the electrical connection in the accused battery. The Plaintiff’s infringement theory for the '581 Patent (a foil held by pressure) appears to be in direct tension with its theory for the '858 Patent, which alleges a welded connection for the same battery.

V. Key Claim Terms for Construction

Term: "closed without being beaded over" ('835 Patent)

  • Context and Importance: This term defines a key departure from a traditional method of sealing button cells. Its construction is critical to determining infringement and is complicated by the IPR history. Practitioners may focus on this term because the substitute claim 14, which replaced the asserted claim, clarifies this concept by adding the limitation that the housing parts "are held together by a force-fitting connection" ('835 Patent, IPR Cert., col. 2:30-32).
  • Intrinsic Evidence for a Broader Interpretation: The specification contrasts the invention with the traditional method of "beading the edge of the cell cup over the edge of the cell top" ('835 Patent, col. 2:5-8), suggesting the term could encompass any closing method that avoids this specific action.
  • Intrinsic Evidence for a Narrower Interpretation: The specification explicitly links the "not beaded over" design to one with an "exclusively force-fitting connection" between the housing parts ('835 Patent, col. 6:49-54). The prosecution history from the IPR, which added this language into the claims, provides strong evidence for a narrower construction.

Term: "output conductor comprising a foil resting flat" ('581 Patent)

  • Context and Importance: This term describes the physical and electrical interface between the battery's internal winding and its external housing. Its definition is critical because the Plaintiff has presented conflicting theories for the same accused product: that it infringes the '581 patent via a foil "resting flat" (Compl. ¶52) and the '858 patent via a "weld bead" (Compl. ¶76). Furthermore, the substitute claim that replaced asserted claim 1 of the '581 patent now explicitly requires a "weld" ('581 Patent, IPR Cert., col. 2:1-5).
  • Intrinsic Evidence for a Broader Interpretation: The plain language of the original claim suggests a simple physical contact maintained by pressure, without requiring a weld or other permanent bond ('581 Patent, col. 12:8-12).
  • Intrinsic Evidence for a Narrower Interpretation: The patent family's disclosure of welding as a separate connection method (as seen in the '858 patent) suggests that "resting flat" was intended to mean a non-welded connection. The IPR history, which cancelled this claim in favor of one requiring a weld, strongly supports the view that these are distinct, mutually exclusive connection types.

VI. Other Allegations

Indirect Infringement

The complaint does not contain specific allegations to support claims of indirect infringement (inducement or contributory infringement). The infringement counts are limited to direct infringement under 35 U.S.C. § 271(a) and importation of a product made by a patented process under § 271(g).

Willful Infringement

The complaint does not allege facts to support a claim for willful infringement, such as pre-suit knowledge of the patents. The prayer for relief includes a request for a finding of an exceptional case under 35 U.S.C. § 285, but the factual predicate for willfulness is not pleaded in the body of the complaint (Compl. p. 17).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of procedural viability: Given that all originally asserted claims were cancelled during post-filing IPR proceedings, can the Plaintiff successfully amend its complaint to assert the new, narrower substitute claims? If so, a key question will be whether the factual allegations concerning the accused M1254S2 battery can satisfy the additional, more stringent limitations (e.g., "force-fitting connection," connection via a "weld") present in those substitute claims.
  • A key evidentiary question will be one of technical contradiction: How is the electrical connection inside the accused battery actually made? The complaint advances seemingly mutually exclusive theories—a connection via a "foil resting flat" for the '581 patent and a "weld bead" for the '858 patent—raising the question of whether proof of one theory would necessarily disprove the other.
  • The ultimate infringement analysis may turn on a question of definitional scope: Can the term "foil resting flat" (from the original '581 patent claims) be construed to read on a welded connection, or are these fundamentally distinct mechanisms? The resolution of this, in light of the extensive IPR history for the entire patent family, will be critical to what remains of the case.