DCT

1:25-cv-00921

Proterra Powered LLC v. Estes Energy Solutions Inc

Log In
Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00921, D. Del., 11/03/2025
  • Venue Allegations: Venue is based on both parties being Delaware corporations and therefore residing in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s electric vehicle battery systems infringe a patent related to a centralized architecture for managing and protecting multiple battery packs.
  • Technical Context: The technology addresses the design of modular, high-voltage battery systems for commercial electric vehicles, a critical and rapidly growing market segment.
  • Key Procedural History: The complaint alleges that three of the patent's named inventors resigned from Plaintiff to found Defendant. Based on this fact, the complaint asserts that the doctrine of assignor estoppel should prevent Defendant from challenging the validity of the patent-in-suit.

Case Timeline

Date Event
2021-03-17 ’677 Patent Priority Date
2022-06-15 ’677 Patent Application Filing Date
2023-05-XX Proterra's then-CTO (and inventor) presents prototype at ACT Expo
2024-02-09 Inventor Dustin Grace and inventor David Lai resign from Proterra
2024-02-26 Defendant Estes Energy Solutions, Inc. is incorporated in Delaware
2024-03-01 Inventor Cagkan Yildiz resigns from Proterra
2024-11-XX Defendant Estes announces its market launch
2025-05-20 ’677 Patent Issue Date
2025-07-22 Original Complaint Filing Date (referenced in Amended Complaint)
2025-11-03 Amended Complaint Filing Date

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

U.S. Patent No. 12,308,677 - "Battery System"

The patent-in-suit is U.S. Patent No. 12,308,677, issued May 20, 2025 (the "’677 Patent").

The Invention Explained

  • Problem Addressed: The patent's background section describes conventional battery packs for electric vehicles as often being bulky, having "inflexible dimensions," and occupying "substantial physical space," which imposes significant design constraints on vehicle manufacturers (Compl. ¶1; ’677 Patent, col. 1:30-44).
  • The Patented Solution: The invention proposes a modular battery system architecture where multiple individual battery packs are connected in parallel to a single, centralized battery management device (BMD) (’677 Patent, Fig. 9; col. 13:35-44). This central BMD contains system-level protective components, such as a "primary contactor" and "primary active fuse," designed to manage and protect the entire array of battery packs simultaneously (Compl. ¶25; ’677 Patent, col. 3:16-26). This approach contrasts with systems where complex control and safety hardware is duplicated within each individual battery pack (Compl. ¶25).
  • Technical Importance: This centralized architecture was designed to lower the bill of materials cost and reduce hardware redundancy, allowing for more scalable and flexible battery solutions for a variety of commercial vehicles (Compl. ¶25-26).

Key Claims at a Glance

The complaint asserts independent claims 11 and 14 and reserves the right to assert dependent claims (Compl. ¶51).

  • Independent Claim 11 (System Claim):

    • A plurality of battery packs, each comprising a plurality of battery cells enclosed within a housing and an active overcurrent protection device.
    • A battery management device comprising a primary automatic disconnect device and a primary contactor.
    • The battery management device is electrically connected to each of the battery packs and configured to control the electrical output.
    • The primary contactor is configured to protect all of the battery packs by being opened when a system current has exceeded a contactor maximum current threshold.

  • Independent Claim 14 (Method Claim):

    • Electrically connecting together a plurality of battery packs to a battery management device.
    • Controlling, by the battery management device, the electrical output of the plurality of battery packs.
    • Determining if a system current has exceeded a contactor maximum current threshold.
    • Protecting, by a primary contactor of the battery management device, all of the plurality of battery packs by opening the primary contactor in response to the determination.

III. The Accused Instrumentality

Product Identification

  • The accused products are the Estes battery systems, including the "Parvus™" and "Magnus™" models (Compl. ¶35).

Functionality and Market Context

  • The complaint describes the accused products as battery systems marketed for multiple applications that directly compete with Proterra, such as heavy-duty trucks, medium-duty vehicles, and buses (Compl. ¶39).
  • The systems are alleged to be "chemistry agnostic" and to use "standardized subpacks" that can be mixed and are "fully scalable" (Compl. ¶37-38). The complaint alleges that after the original lawsuit was filed on July 22, 2025, Estes changed its website's marketing description from a "single-interface stacks" system to "Single and Multi-String Battery Packs" (Compl. ¶36).
  • The complaint alleges that Estes has "made" and "used" the accused battery system in the United States, at least for testing purposes, but contends Estes has "not yet in fact offered to sell or sell" the system (Compl. ¶47).

IV. Analysis of Infringement Allegations

The complaint alleges that Estes has infringed and continues to infringe one or more claims of the ’677 Patent, including at least claims 11 and 14, by making and/or using the Estes battery systems in the United States (Compl. ¶51). The complaint’s infringement theory is heavily predicated on the fact that the individuals who founded Estes are the same Proterra employees who "designed and developed the key innovations and battery technology that became the subject of the ’677 Patent" (Compl. ¶49).

The complaint states that a detailed, element-by-element infringement analysis is provided in an attached claim chart (Exhibit L) (Compl. ¶48, ¶51). As this exhibit was not included with the complaint, a detailed analysis of the technical mapping between the claim elements and the accused product's features is not possible from the complaint itself. No probative visual evidence provided in complaint.

  • Identified Points of Contention:
    • Scope Questions: A central question may be whether the Estes system’s architecture includes a single, centralized "battery management device" with a "primary contactor" that protects "all" battery packs, as required by the claims. The dispute could focus on whether Estes's control and safety functions are distributed across its "subpacks" in a manner that falls outside the claimed centralized architecture.
    • Technical Questions: The complaint does not specify which components of the Estes system allegedly constitute the "active overcurrent protection device" in each pack or the "primary automatic disconnect device" in the management unit. Evidence establishing the structure and function of these specific components in the accused system will be critical.

V. Key Claim Terms for Construction

  • The Term: "battery management device"

    • Context and Importance: The definition of this term is fundamental to the infringement analysis. The case may turn on whether the accused Estes system contains a single, centralized component that meets this definition, or if its control architecture is sufficiently different (e.g., more distributed) to be non-infringing.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes the "battery management device 810" in functional terms, stating it includes "circuitry and logic for managing functionality of the battery packs," such as power distribution, charging, and monitoring (Compl. ¶25-26; ’677 Patent, col. 13:28-34). This functional language could support a construction that is not limited to a specific physical form factor.
      • Evidence for a Narrower Interpretation: The patent's primary embodiment, shown in Figure 9, depicts the "battery management device 810" as a distinct, singular hardware unit to which all individual battery packs connect (’677 Patent, Fig. 9). This depiction could be used to argue that the term requires a single, physically consolidated control unit.

  • The Term: "primary contactor"

    • Context and Importance: Both asserted independent claims require a "primary contactor" that protects "all of the plurality of battery packs." The infringement determination will depend on whether the Estes system has a component that performs this specific, system-wide protective function.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The term could be construed functionally to cover any contactor or set of contactors that collectively achieves the objective of protecting the entire system from overcurrent events, regardless of its physical implementation.
      • Evidence for a Narrower Interpretation: Claim 11 explicitly recites "a primary contactor" (singular) that is part of the "battery management device" and is "configured to protect all of the plurality of battery packs" (’677 Patent, col. 24:16-24). This language may support a narrower construction requiring a single, system-level component responsible for protecting the entire array of packs.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that should Estes begin selling its systems, it will induce infringement by "intentionally instructing or otherwise encouraging" customers to use the systems in an infringing manner, citing its marketing materials (Compl. ¶53). It further alleges contributory infringement, asserting the Estes systems are a "material part of the claimed inventions" and have "no other substantial use" (Compl. ¶54).
  • Willful Infringement: The willfulness allegation is based on alleged pre-suit knowledge of the patent's technology. The complaint asserts that because the founders of Estes are the named inventors on the ’677 Patent who developed the technology at Proterra, they had "full knowledge of Proterra's exclusive rights" and used "insider knowledge to compete directly" (Compl. ¶49).

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

  • A core issue will be one of architectural equivalence: does the accused Estes battery system implement the centralized control and protection architecture defined by the claims' "battery management device" and "primary contactor," or does its design differ in a material, non-infringing way?
  • A dispositive legal question will be the applicability of assignor estoppel: to what extent will the defendant—founded and led by the very inventors who assigned their patent rights to the plaintiff—be barred from challenging the patent's validity, thereby narrowing the case to the sole issue of infringement?
  • A key evidentiary question will concern acts of infringement: given the complaint's assertion that Estes has made and used the system for testing but has not yet offered it for sale, what specific acts constituting infringement under 35 U.S.C. § 271(a) can be proven, and how will this affect the timeline and scope of potential damages?