LithiumHub LLC v. Renogy New Energy Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: LithiumHub, LLC (South Carolina) and LithiumHub Technologies, LLC (Texas)
  • Defendant: Renogy New Energy Co., Ltd (People's Republic of China)
  • Plaintiff’s Counsel: Dority & Manning, P.A.
• Case Identification: 5:24-cv-00136, E.D. Tex., 09/13/2024
• Venue Allegations: Venue is alleged to be proper because the defendant is a foreign entity not resident in the United States, allowing suit in any judicial district. The complaint also alleges that infringing products are sold within the Eastern District of Texas.
• Core Dispute: Plaintiff alleges that Defendant’s lithium-ion batteries, including its "Core," "Pro," and "Smart" series, infringe patents related to solid-state control circuits for detecting and correcting fault conditions.
• Technical Context: The technology concerns advanced battery management systems that use solid-state switches to protect lithium-ion batteries from over-charging, over-discharging, and short circuits, enhancing safety and performance in applications like deep-cycle storage and engine starting.
• Key Procedural History: The complaint alleges that Defendant was put on notice of the asserted patents and its infringement through an International Trade Commission (ITC) complaint filed by Plaintiff on September 12, 2024. The complaint also notes that the inventor repurchased the patents in 2020 following the bankruptcy of a prior assignee, StarkPower, Inc.

Case Timeline

Date	Event
2010-11-29	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	Plaintiff files ITC Complaint against Defendant
2024-09-13	Complaint Filing Date

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

U.S. Patent No. 9,412,994, Lithium Starter Battery and Solid State Switch Therefor, Issued Aug. 9, 2016

The Invention Explained

• Problem Addressed: The patent's background section describes the limitations of conventional lead-acid starter batteries, noting they are heavy, have a short operational life, and suffer from high internal resistance, especially in cold weather. It also identifies safety and reliability issues with existing protection circuits, such as mechanical relays that can weld shut during high-current events (’994 Patent, col. 1:26-34; col. 2:15-29).
• The Patented Solution: The invention proposes a lithium-ion battery system incorporating a "unique configuration" of solid-state switches (e.g., MOSFETs) to manage battery operation. The core of the solution is an arrangement of switch pairs in parallel, where the "Sources" or "Drains" of the switches within each pair are electrically tied together (’994 Patent, col. 2:36-56). This topology, as depicted in circuit diagrams like Figure 17, allows a controller to independently manage the charging and discharging paths, for instance, by shutting off the charging path to prevent over-voltage while still permitting the battery to supply power (’994 Patent, col. 9:10-19; Compl. ¶20).
• Technical Importance: This design offers a more robust and granular control method for high-power lithium batteries compared to conventional relays, enabling safer and more efficient performance that makes them a viable replacement for traditional lead-acid batteries in demanding applications (’994 Patent, col. 3:20-32).

Key Claims at a Glance

• The complaint asserts independent claims 1 and 14 (Compl. ¶¶ 35, 51).
• Independent Claim 1 recites a battery pack that includes:
  • A battery pack housing
  • At least one lithium-based rechargeable cell
  • A circuit board with a balancing and cutoff function, which includes "a plurality of pairs of solid state switches"
  • Each pair of switches is connected in a "parallel configuration to another pair of solid state switches"
  • The switches within a pair are configured such that "either the drains of the switches are connected or the sources of the switches are connected"
  • This parallel configuration of switches is connected in series with the battery cell(s)
• Independent Claim 14 recites a similar battery pack for a 1 volt to 120 volt system, but recites a circuit board with only a "cutoff function" and omits the "balancing" function requirement.
• The complaint reserves the right to assert additional claims (Compl. ¶35).

U.S. Patent No. 9,954,207, Lithium Battery with Solid State Switch, Issued Apr. 24, 2018

The Invention Explained

• Problem Addressed: As a continuation-in-part, the '207 Patent addresses the same technical problems as its parent, the '994 Patent: the shortcomings of lead-acid batteries and the unreliability of conventional protection mechanisms (’207 Patent, col. 1:30-38; col. 2:20-30).
• The Patented Solution: The patent again describes the solid-state switching apparatus using pairs of switches in a parallel arrangement. The description clarifies that this invention is also "useful as a Deep Cycle battery," expanding its applicability beyond the engine starter context (’207 Patent, Abstract). The core control concept of independently managing charge and discharge paths via the unique switch configuration remains central to the invention (’207 Patent, col. 9:43-53).
• Technical Importance: The invention extends the patented battery protection technology to a broader market, including deep-cycle applications such as marine use, recreational vehicles, and off-grid power systems, where long-term reliability and safety are critical (’207 Patent, col. 5:5-9).

Key Claims at a Glance

• The complaint asserts independent claims 1 and 12 (Compl. ¶74).
• Independent Claim 1 recites a battery pack for powering an electric motor, including the core "solid state switching apparatus" with the "plurality of pairs of solid state switches" in the specific parallel configuration where drains or sources are connected.
• Independent Claim 12 recites a "deep cycle battery" that includes a "battery management system" for protecting against faults (e.g., overvoltage, undervoltage, reverse polarity), where the system comprises the specific solid-state switching apparatus of Claim 1.
• The complaint reserves the right to assert additional claims (Compl. ¶58).

III. The Accused Instrumentality

• Product Identification: The complaint names Defendant's "Core," "Pro," and "Smart" series of Lithium-Ion batteries, providing a list of over a dozen specific SKUs (Compl. ¶¶ 7, 25). The "Renogy 12V 100Ah Smart Lithium Iron Phosphate Battery (SKU: RBT100LFP12S)" is identified as a representative accused product (Compl. ¶¶ 35, 58).
• Functionality and Market Context: The accused products are deep-cycle lithium iron phosphate (LiFePO4) batteries (Compl. ¶25). The complaint alleges these products are sold for use in applications such as RVs and off-grid power systems through major U.S. retailers, including Lowe's Home Improvement, and online through Defendant’s website (Compl. ¶¶ 8, 27). A photograph included in the complaint shows a Renogy battery with its top cover removed, revealing internal components including a circuit board, cells, and wiring (Compl. p. 9). Another visual is a screenshot from the Lowe's website showing the "Smart Lithium Iron Phosphate Battery" offered for sale, which highlights its "Multiple Protections" (Compl. p. 4).

IV. Analysis of Infringement Allegations

The complaint alleges that the accused Renogy batteries directly infringe the asserted patents by containing the claimed inventions (Compl. ¶24). The infringement counts state that detailed claim charts demonstrating how the representative product meets each limitation of the asserted claims are attached as Exhibits E and F (Compl. ¶¶ 35, 58). However, these exhibits were not included with the complaint as filed.

The complaint's narrative infringement theory, based on its general allegations, is that the accused batteries contain an internal battery management system with solid-state switches (Compl. p. 9, photo) that embody the patented circuit configuration (Compl. ¶20). This circuitry allegedly provides protection against fault conditions by independently controlling the charging and discharging paths, thereby practicing the patented invention (Compl. ¶¶ 1, 20).

• Identified Points of Contention:
  • Technical Evidence: A primary point of contention will be the factual question of whether the accused products' internal circuits actually contain the specific architecture required by the claims. The analysis will depend on evidence from reverse engineering the products to determine if they practice the "plurality of pairs of solid state switches" with either their "drains" or "sources" connected, as claimed.
  • Scope of "Starter Battery" ('994 Patent): For the '994 Patent, titled Lithium Starter Battery, a potential dispute may arise over whether its claims should be limited to engine starting applications. The defense could argue the patent's focus on "starter" batteries limits its scope, while the plaintiff may argue the claim language itself is not so limited.
  • Scope of "Battery Management System" ('207 Patent): For claim 12 of the ’207 Patent, a question will be whether the accused product's internal circuitry meets the definition of a "battery management system" that performs all the protective functions recited in the claim.

V. Key Claim Terms for Construction

• The Term: "a plurality of pairs of solid state switches connected in a parallel configuration to another pair of solid state switches" ('994 Patent, Claim 1; '207 Patent, Claim 1).

• Context and Importance: This phrase describes the core architecture of the claimed invention. The infringement analysis for all asserted independent claims will turn on whether the accused products' circuitry embodies this specific topology.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claims use the general term "solid state switches," and the specification provides a non-exhaustive list including "FET, a MOSFET... or IGBT" (’994 Patent, col. 2:36-41), which may support a construction not limited to a single type of switch.
  • Evidence for a Narrower Interpretation: The specification repeatedly describes this as a "unique configuration" and an "unconventional approach" (’994 Patent, col. 2:39-41, col. 9:1-3). The detailed description and figures (e.g., Figs. 16-23) exclusively show pairs of switches whose "Sources" or "Drains" are directly tied together. A party could argue the term should be construed as being limited to this specific disclosed arrangement.

• The Term: "circuit board... configured to balance each individual cell" ('994 Patent, Claim 1).

• Context and Importance: This functional limitation is present in Claim 1 of the '994 Patent but absent from Claim 14. Its construction is important for distinguishing the scope of these two claims and determining if the accused products, which may or may not have this specific function, infringe Claim 1.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent provides a high-level description of balancing as the "process of forcing all of the cells to have identical voltages" (’994 Patent, col. 7:25-28), which could be read to cover any method achieving that result.
  • Evidence for a Narrower Interpretation: The patent does not detail a specific circuit for balancing, but a party could argue that the term implies an active balancing circuit as opposed to simpler passive methods, potentially narrowing the scope of the claim.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement under 35 U.S.C. § 271(b) (Compl. ¶28). The factual basis for this allegation is that Defendant manufactures the products for the U.S. market, promotes them on its website and through retailers like Lowe's, and provides them to importers and distributors, thereby encouraging and intending for end-users to commit acts of direct infringement (Compl. ¶¶ 28-29, 34).
• Willful Infringement: Willfulness is alleged based on Defendant’s purported knowledge of the asserted patents and its infringement "at least since a complaint was filed against them at the International Trade Commission on September 12, 2024" (Compl. ¶31). The complaint alleges that continued infringement after this date constitutes willful and exceptional conduct, justifying enhanced damages and attorneys' fees (Compl. ¶¶ 55, 78).

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

• A core issue will be one of technical evidence: Can the Plaintiff demonstrate through product teardowns and expert analysis that the accused Renogy batteries contain the specific "unconventional" circuit topology recited in the claims—namely, parallel-connected pairs of solid-state switches with their sources or drains electrically tied together? The outcome of the case will likely depend heavily on this factual determination.
• A central legal issue will be one of claim construction: The dispute will likely focus on the proper scope of the term "a plurality of pairs of solid state switches connected in a parallel configuration." How the court construes this foundational language will dictate the boundaries of the invention and whether the specific design implemented by the Defendant, once fully understood, falls within them.
• A key question for damages will be willfulness: Does notice via an ITC complaint filed one day prior to the district court action, followed by continued sales, constitute the type of "egregious" conduct necessary to support a finding of willfulness and enhanced damages, or will it be considered part of a standard litigation defense posture?