DCT

5:24-cv-00137

LithiumHub LLC v. Shenzhen Yichen S Power Tech Co Ltd

Log In

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 5:24-cv-00137, E.D. Tex., 09/13/2024
  • Venue Allegations: Venue is alleged to be proper because Defendant is a foreign corporation not resident in the United States and may therefore be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendant’s "Dakota Lithium" brand lithium-ion batteries infringe two patents related to control circuits that use a specialized solid-state switch configuration for fault detection and protection.
  • Technical Context: The technology concerns advanced Battery Management Systems (BMS) for lithium-ion batteries, which are critical for ensuring the safety, longevity, and performance of batteries in high-power applications.
  • Key Procedural History: The named inventor, Martin Koebler, is alleged to have filed provisional patent applications in 2010 and 2011. The asserted patents were later acquired by Mr. Koebler from the bankruptcy estate of his former company, StarkPower, Inc., in 2020. The complaint alleges Defendant had knowledge of the patents and infringement based on an International Trade Commission (ITC) complaint filed against it on September 12, 2024, one day prior to the filing of this lawsuit.

Case Timeline

Date Event
2010-11-29 Earliest Priority Date for ’994 and ’207 Patents
2016-08-09 U.S. Patent No. 9,412,994 Issued
2018-04-24 U.S. Patent No. 9,954,207 Issued
2024-09-12 ITC Complaint Filed Against Defendant (per complaint allegations)
2024-09-13 Complaint Filed

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

U.S. Patent No. 9,412,994, “Lithium Starter Battery and Solid State Switch Therefor,” issued August 9, 2016

The Invention Explained

  • Problem Addressed: The patent describes conventional lead-acid starter batteries as heavy, bulky, and inefficient, especially in cold weather (Compl. ¶16; ’994 Patent, col. 1:26-34). It notes that while protection circuits are necessary to prevent dangerous conditions like over-charging or over-discharging in more advanced batteries, they can be complex and introduce performance losses (’994 Patent, col. 1:40-47).
  • The Patented Solution: The invention proposes a control circuit for lithium-ion batteries that uses a "unique configuration" of solid-state switches, such as MOSFETs (’994 Patent, col. 2:36-40). This configuration involves arranging pairs of switches in parallel, with the "Sources" or "Drains" of the switches within each pair electrically tied together (’994 Patent, col. 2:40-45; Fig. 16). This design is intended to allow for simplified, independent control over the charging and discharging current pathways, thereby protecting the battery from fault conditions without the drawbacks of conventional relays or simpler switches (Compl. ¶20; ’994 Patent, col. 9:1-24).
  • Technical Importance: This circuit architecture allows for finer control over battery operation, enabling one pathway (e.g., discharging) to be active while another (e.g., charging) is disabled, which is a critical feature for managing the health and safety of high-power lithium-ion battery packs (’994 Patent, col. 9:11-24).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 14 (Compl. ¶32).
  • Independent Claim 1 recites:
    • A battery pack for a 12 to 120 volt system with a housing and at least one lithium-based cell.
    • A circuit board within the housing configured to balance each cell and having a cutoff function.
    • The circuit board includes a "plurality of pairs of solid state switches" with each pair connected in a "parallel configuration to another pair."
    • Within a pair, the switches are configured such that either their "drains... are connected or the sources... are connected."
    • This parallel switch arrangement is connected in series with the battery cell(s).
  • Independent Claim 14 is similar to Claim 1 but is directed to a 1 to 120 volt system and recites a "cutoff function" without the additional "balance" function limitation.
  • The complaint reserves the right to assert additional claims (Compl. ¶33).

U.S. Patent No. 9,954,207, “Lithium Battery with Solid State Switch,” issued April 24, 2018

The Invention Explained

  • Problem Addressed: The patent addresses the same problems as the ’994 Patent regarding the limitations of lead-acid batteries and the need for effective, efficient protection circuits for lithium-ion batteries (’207 Patent, col. 1:30-58).
  • The Patented Solution: The ’207 Patent, a continuation-in-part of the ’994 Patent application, discloses the same solid-state switching architecture based on parallel pairs of switches with connected sources or drains (’207 Patent, col. 2:35-60). The patent expands the stated utility of this invention to include deep cycle batteries in addition to starter batteries (’207 Patent, Abstract).
  • Technical Importance: This extends the applicability of the core protective circuit design to a broader market of energy storage applications beyond engine starting, such as for marine, RV, or off-grid power systems (’207 Patent, col. 13:51-56).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 12 (Compl. ¶55).
  • Independent Claim 1 recites:
    • A battery pack for starting an internal combustion engine in a 6 to 48 volt system.
    • A housing, at least one lithium-based cell, and a "solid state switching apparatus."
    • The apparatus comprises the "plurality of pairs of solid state switches" in the parallel configuration where drains or sources are connected, as described in the ’994 Patent.
  • Independent Claim 12 recites:
    • A deep cycle battery for a 6 to 800 volt system.
    • A housing, at least one lithium-based cell, and a "battery management system" that protects against various fault conditions.
    • The battery management system comprises the same "solid state switching apparatus" with the parallel-pair configuration.
  • The complaint reserves the right to assert additional claims (Compl. ¶57).

III. The Accused Instrumentality

  • Product Identification: The complaint names a range of "Dakota Lithium" branded lithium-ion batteries, collectively referred to as the "Accused Products" (Compl. ¶¶ 8, 26). The "Dakota Lithium 12V 100AH Deep Cycle LiFePo4 Battery" is identified as a representative example (Compl. ¶33). A screenshot from the defendant's website shows the representative accused product, a "Dakota Lithium 12V 100AH Deep Cycle LiFePO4 Battery" (Compl. p. 8).
  • Functionality and Market Context: The Accused Products are described as lithium-ion batteries that serve as replacements for traditional lead-acid batteries in deep cycle and engine starter applications (Compl. p. 8). The complaint alleges these products are sold for use in boats, RVs, solar energy storage, and other applications (Compl. p. 8). It further alleges that the products are sold through Defendant’s website, its Amazon store, and a network of U.S. distributors and retailers (Compl. ¶¶ 25, 28). A screenshot from the defendant's website shows a "Dealers & Retail Partners" locator, listing retailers in the United States (Compl. p. 9).

IV. Analysis of Infringement Allegations

The complaint alleges that the Accused Products infringe but references claim chart exhibits that were not filed with the complaint (Compl. ¶¶ 33, 56). Therefore, the following is a summary of the infringement theory as described in the body of the complaint.

  • Infringement Theory Summary:

    • ’994 Patent: The complaint alleges that the Accused Products, as represented by the Dakota Lithium 12V 100AH battery, satisfy every element of at least claims 1 and 14 (Compl. ¶¶ 33-48). The core of the allegation is that the built-in Battery Management System (BMS) of the accused batteries constitutes the claimed "circuit board" and contains the specific "solid state switching apparatus" with a "plurality of pairs of solid state switches" connected in the claimed parallel configuration with interconnected drains or sources (Compl. ¶¶ 37-39, 45-47).
    • ’207 Patent: The complaint makes parallel allegations for claims 1 and 12 of the ’207 Patent, stating that the BMS in the Accused Products functions as the claimed "solid state switching apparatus" and "battery management system" for both starter and deep cycle applications (Compl. ¶¶ 56-71). The allegations similarly depend on the internal circuitry of the accused batteries matching the specific switch configuration claimed in the patent (Compl. ¶¶ 60-62, 67-70).

  • Identified Points of Contention:

    • Technical Question: The primary factual question is whether the BMS circuitry inside the accused Dakota Lithium batteries actually implements the architecture recited in the claims. Specifically, what evidence does the complaint provide that the accused BMS contains a "plurality of pairs of solid state switches" arranged in a parallel configuration where the "drains... are connected or the sources... are connected"? The complaint makes this allegation by reference to an un-provided exhibit and does not include schematics or reverse-engineering results.
    • Scope Questions: A central legal dispute may arise over the scope of the claims. For example, does the term "a plurality of pairs of solid state switches," which is illustrated in the patents with discrete transistor components, read on a modern, highly integrated semiconductor BMS chip where the concepts of discrete "pairs" and "connections" may be less distinct?

V. Key Claim Terms for Construction

  • The Term: "a plurality of pairs of solid state switches with each pair of solid state switches connected in a parallel configuration to another pair of solid state switches" (’994 Patent, cl. 1)

  • Context and Importance: This phrase describes the core structure of the claimed invention. The infringement analysis for all asserted claims will hinge on whether the accused products contain a circuit that meets this specific architectural definition. Practitioners may focus on this term because it appears to describe a very particular circuit topology that may or may not be present in a standard commercial BMS.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification describes the function of this arrangement as allowing for "user friendly reactivation of the circuit without any pushbuttons or reset buttons" and enabling independent control of charge and discharge currents (’994 Patent, col. 9:20-24). A party might argue the term should be construed functionally to cover any structure that achieves this parallel, independent control.
    • Evidence for a Narrower Interpretation: The patent figures, such as Figure 16, provide a specific schematic showing discrete pairs of transistors (labeled T1, T2) whose outputs are then combined in parallel. A party could argue the claims should be limited to this or a similar discrete-component-based implementation, as explicitly "shown" and described (’994 Patent, Fig. 16; col. 2:40-45).

  • The Term: "configured such that either the drains of the switches are connected or the sources of the switches are connected" (’994 Patent, cl. 1)

  • Context and Importance: This limitation defines the internal connection within each "pair" of switches, which the patent calls an "unconventional approach" (’994 Patent, col. 9:1-2). Proving that the accused products have this specific internal configuration will be crucial for the plaintiff.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The term "connected" could be interpreted broadly as "electrically connected," which might encompass connections within a single integrated circuit rather than requiring two separate components to be wired together.
    • Evidence for a Narrower Interpretation: The specification consistently illustrates this concept using schematic diagrams with distinct transistor symbols having their source or drain terminals explicitly tied together (’994 Patent, Figs. 14-23). This may support an interpretation that requires a structure analogous to the discrete connections shown.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement under 35 U.S.C. § 271(b) (Compl. ¶27). The factual basis for inducement includes allegations that Defendant manufactures products for the U.S. market, advertises them for sale in the U.S., and actively refers potential customers to U.S.-based retailers through a dealer locator on its website (Compl. ¶28).
  • Willful Infringement: Willfulness is alleged based on Defendant having actual or constructive knowledge of the Asserted Patents and its infringement from "at least since a complaint was filed against them at the International Trade Commission on September 12, 2024" (Compl. ¶¶ 29, 50, 73).

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

This case appears to present two central questions for the court's determination:

  • A core issue will be one of evidentiary proof: What is the actual circuit architecture of the Battery Management System (BMS) inside the accused Dakota Lithium products? The outcome of the case will likely depend on technical evidence, obtained through discovery or reverse engineering, establishing whether the accused BMS in fact practices the specific "parallel pair" solid-state switch configuration required by every asserted claim.
  • A key legal issue will be one of claim scope: Can the claims, which describe a switch apparatus using terms like "pairs" and "connected" and are illustrated with discrete components, be construed to cover a modern, highly integrated circuit on a single semiconductor chip? The court's construction of these terms will define the technological scope of the patent and may be dispositive of infringement.