DCT

2:25-cv-01133

Bunker Hill Tech LLC v. Toyota Motor Corp

Log In
Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-01133, E.D. Tex., 11/18/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants are subject to personal jurisdiction in the district, have committed acts of patent infringement in the district, and maintain at least one regular and established place of business in the district, specifically identifying a Plano, Texas address.
  • Core Dispute: Plaintiff alleges that Defendant’s Toyota- and Lexus-branded vehicles with electric or hybrid-electric powertrain systems infringe nine U.S. patents related to electric vehicle charging, energy management, and powertrain control systems.
  • Technical Context: The patents-in-suit relate to technologies for managing power in electric and hybrid vehicles, a critical area for improving efficiency, range, and charging speed in the rapidly growing electric vehicle market.
  • Key Procedural History: The complaint alleges that Plaintiff, through its licensing agent, provided Defendant with notice of infringement and claim charts for all asserted patents on various dates between August and November 2025, following initial contact in November 2024. These allegations form the basis for Plaintiff's claim of willful infringement.

Case Timeline

Date Event
2009-03-11 U.S. Patent No. 8,086,364 Priority Date
2009-08-31 U.S. Patent No. 8,030,884 Priority Date
2009-12-18 U.S. Patent Nos. 9,914,365; 10,442,296; 10,549,648 Priority Date
2011-09-06 U.S. Patent No. 8,326,467 Priority Date
2011-10-04 U.S. Patent No. 8,030,884 Issue Date
2011-12-27 U.S. Patent No. 8,086,364 Issue Date
2012-12-03 U.S. Patent Nos. 10,291,158; 10,374,529; 11,374,508 Priority Date
2012-12-04 U.S. Patent No. 8,326,467 Issue Date
2018-03-13 U.S. Patent No. 9,914,365 Issue Date
2019-05-14 U.S. Patent No. 10,291,158 Issue Date
2019-08-06 U.S. Patent No. 10,374,529 Issue Date
2019-10-15 U.S. Patent No. 10,442,296 Issue Date
2020-02-04 U.S. Patent No. 10,549,648 Issue Date
2022-06-28 U.S. Patent No. 11,374,508 Issue Date
2024-11-20 Toyota allegedly put on notice regarding a potential license to BHT assets.
2025-08-22 Plaintiff's agent allegedly sent email with claim charts for six of the Asserted Patents.
2025-08-25 Toyota allegedly downloaded the claim charts provided on August 22.
2025-10-22 Plaintiff's agent allegedly sent email with a claim chart for the ’365 Patent.
2025-11-06 Plaintiff's agent allegedly sent email with claim charts for the ’364 and ’508 Patents.
2025-11-18 Complaint Filing Date

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

U.S. Patent No. 8,030,884 - "Apparatus for transferring energy using onboard power electronics and method of manufacturing same," issued October 4, 2011

The Invention Explained

  • Problem Addressed: The patent addresses the cost and weight added to electric or hybrid vehicles by dedicated battery charging circuitry used for recharging from an external source. (’884 Patent, col. 1:43-53).
  • The Patented Solution: The invention proposes using the vehicle's existing onboard power electronics—those normally used for driving the motor—to also manage the charging process. It describes a system with a controller that monitors the transfer of charging energy and, after a certain threshold is met, uses a "bi-directional voltage modification assembly" to control the voltage or current supplied to the vehicle's battery. (’884 Patent, Abstract; col. 2:1-11).
  • Technical Importance: This approach suggests a way to reduce vehicle complexity and cost by leveraging dual-use components, a key engineering goal in vehicle design. (’884 Patent, col. 1:54-61).

Key Claims at a Glance

  • The complaint asserts independent claim 20. (Compl. ¶38).
  • Essential elements of Claim 20 include:
    • A system comprising: a charge bus configured to receive charging energy from a voltage source;
    • an energy storage device configured to output a DC voltage and coupled to the charge bus;
    • a first bi-directional voltage modification assembly coupled to the charge bus; and
    • a controller configured to monitor the transfer of charging energy, compare it with a threshold, and control the bi-directional assembly to modify the voltage or current supplied to the energy storage device after the threshold is crossed.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 8,086,364 - "System and method for operation of electric and hybrid vehicles," issued December 27, 2011

The Invention Explained

  • Problem Addressed: Conventional control schemes for hybrid vehicles may not optimize battery usage because they lack historical knowledge of a specific route. This can lead to inefficiencies like having a full battery when regenerative braking opportunities are available, or depleting the battery before an uphill climb where it would be most useful. (’364 Patent, col. 1:49-col. 2:20).
  • The Patented Solution: The invention describes a method for energy management that uses a historical power-use database. The system identifies the vehicle's current location on a map, uses algorithms to pre-screen potential upcoming road segments ("links"), matches the vehicle's location to a specific link, and then uploads the power usage data from that trip into the historical database to refine future predictions. (’364 Patent, Abstract; col. 2:50-67).
  • Technical Importance: This "learning" approach to energy management suggests a path to improving vehicle efficiency and battery longevity over time without requiring topographical map data, by relying instead on crowdsourced, real-world driving data. (’364 Patent, col. 2:21-34).

Key Claims at a Glance

  • The complaint asserts independent claim 9. (Compl. ¶52).
  • Essential elements of Claim 9 include:
    • A method comprising: identifying a current location of a vehicle;
    • applying a pre-screening algorithm with respect to a map link and the location, based on a historical power-use database;
    • determining if one or more links are within given bounds;
    • if so, matching the vehicle's current location to the link via a subsequential matching algorithm; and
    • uploading power information used by the vehicle into the historical power-use database.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 8,326,467 - "Controller and method of controlling a power system," issued December 4, 2012

  • Technology Synopsis: The patent relates to a control system for managing power in a vehicle. The system determines operating conditions and can identify a predetermined time for a charging operation, making decisions based on whether charging can complete within that time. (’467 Patent, Abstract).
  • Asserted Claims: At least independent claim 9. (Compl. ¶67).
  • Accused Features: The complaint accuses Toyota's "charge later charging feature," which includes a charging schedule function that allows users to set a departure time. The vehicle's controller allegedly determines if charging can be completed by the set time. (Compl. ¶¶68, 70-71).

U.S. Patent No. 9,914,365 - "Apparatus and method for rapid charging using shared power electronics," issued March 13, 2018

  • Technology Synopsis: The patent describes a vehicle charging system that can utilize both DC and AC connections. It employs a plurality of DC converters (e.g., boost and buck converters) to step up and step down voltage, allowing for charging at different rates depending on the connection type. (’365 Patent, Abstract).
  • Asserted Claims: At least independent claim 5. (Compl. ¶83).
  • Accused Features: The complaint targets vehicles with DC Fast Charging capabilities, which can accept both DC and AC charging inputs. The allegations focus on the vehicle's use of an AC/DC converter and multiple DC converters to manage charging from both sources at different rates. (Compl. ¶¶84-91).

U.S. Patent No. 10,291,158 - "Electric drive system and energy management method," issued May 14, 2019

  • Technology Synopsis: The patent describes an electric drive system with an energy storage system, a power conversion system, and two AC motors. An energy management system selectively enables the motors to operate in different modes, such as both providing torque to drive the vehicle or one acting as a motor while the other acts as a generator. (’158 Patent, Abstract; Claim 22).
  • Asserted Claims: At least independent claim 22. (Compl. ¶101).
  • Accused Features: The complaint accuses Toyota's dual-motor hybrid system (using MG1 and MG2 motor-generators) and its "Hybrid Synergy Drive" system. The allegations focus on the system's ability to combine torque from both motors for driving or use one motor to drive the vehicle while the other generates power. (Compl. ¶¶107-108).

U.S. Patent No. 10,374,529 - "Electric drive system and energy management method," issued August 6, 2019

  • Technology Synopsis: This patent is similar to the '158 Patent, describing a drive system with two motor/generators, a transmission, and a power split device. It claims specific modes of operation, such as using only one motor for cruising and both motors for accelerating. (’529 Patent, Claim 1).
  • Asserted Claims: At least independent claim 1. (Compl. ¶118).
  • Accused Features: The complaint again targets the dual-motor hybrid system (MG1 and MG2), accusing its specific operational modes where only MG2 is used as a motor during cruising, while both MG1 and MG2 are used as motors during acceleration in EV mode. (Compl. ¶¶124-125).

U.S. Patent No. 10,442,296 - "Vehicle propulsion system with multi-channel DC bus and method of manufacturing same," issued October 15, 2019

  • Technology Synopsis: The patent describes a hybrid vehicle system with an energy storage system, a bi-directional DC/DC converter, first and second traction motors, and an electrically variable transmission (EVT) with planetary gears. A control system selectively operates the motors in different modes, including combined motor operation or a motor/generator split. (’296 Patent, Claim 1).
  • Asserted Claims: At least independent claim 1. (Compl. ¶135).
  • Accused Features: The complaint accuses Toyota's hybrid system, identifying the power split device as the claimed EVT, MG1 and MG2 as the traction motors, and the control system that operates the motors to either jointly drive the vehicle or to have MG1 act as a generator while MG2 drives the vehicle. (Compl. ¶¶139, 142-143).

U.S. Patent No. 10,549,648 - "Vehicle propulsion system with multi-channel DC bus and method of manufacturing same," issued February 4, 2020

  • Technology Synopsis: This patent is similar to the '296 Patent, describing a hybrid vehicle propulsion system with two electric motors, a transmission device comprising planetary gears, and a control system. It claims various selective operations, including using one motor as a generator while the other drives, or using the second motor as a generator during regenerative braking. (’648 Patent, Claim 16).
  • Asserted Claims: At least independent claim 16. (Compl. ¶153).
  • Accused Features: The allegations again map to Toyota's hybrid system, accusing the control system's selective operation of MG1 as a generator while MG2 drives, and the operation of MG2 as a generator during regenerative braking. (Compl. ¶¶160-161).

U.S. Patent No. 11,374,508 - "Electric drive system and energy management method," issued June 28, 2022

  • Technology Synopsis: This patent is similar to the '158 and '529 patents, describing a drive system with first and second electric motors, a transmission, and a power split device. It claims an energy management system that enables different modes of operation for cruising, starting, and accelerating. (’508 Patent, Claim 1).
  • Asserted Claims: At least independent claim 1. (Compl. ¶171).
  • Accused Features: The complaint accuses the energy management system of Toyota's hybrid vehicles, focusing on its distinct operational modes: a cruise mode (MG2 motor, MG1 generator), a starting mode (MG1 starts the engine, MG2 drives), and an acceleration mode (both MG1 and MG2 operate as motors). (Compl. ¶¶177-179).

III. The Accused Instrumentality

Product Identification

  • The complaint identifies the "Accused Products" as all Toyota- and Lexus-branded vehicles equipped with electric or hybrid-electric powertrain systems. (Compl. p. 2, fn. 1). Specific exemplary models cited include the 2025 Toyota RAV4 Plug-in Hybrid, 2025 Toyota bZ4X, and 2025 Toyota Prius Plug-in Hybrid. (Compl. ¶¶38, 52, 101).

Functionality and Market Context

  • The accused functionalities span several core systems of modern electric and hybrid vehicles. For charging, the complaint targets the vehicle's ability to receive energy via a charging inlet, manage it with components like DC/DC converters and a battery computer, and support both AC and DC fast charging. (Compl. ¶¶39, 41, 84). For energy management, the allegations focus on the navigation system's ability to use vehicle data (location, battery level) to suggest charging stations and the vehicle's collection of driving data for connected services. (Compl. ¶¶53-54, 57). For the powertrain, the allegations center on Toyota's "Hybrid Synergy Drive" system, which uses two motor-generators (MG1 and MG2), a power control unit, a planetary gear set (power split device), and a sophisticated control system to enable multiple operating modes for driving, charging, and regeneration. (Compl. ¶¶104, 106-108). The complaint provides a diagram from a Toyota owner's manual for the RAV4 Plug-in Hybrid, which labels key system components like the "Hybrid battery," "AC charging inlet," and "DC/DC converter." (Compl. p. 11).
  • The complaint does not provide specific allegations regarding the products' market positioning beyond their general availability for sale in the United States.

IV. Analysis of Infringement Allegations

U.S. Patent No. 8,030,884 Infringement Allegations

Claim Element (from Independent Claim 20) Alleged Infringing Functionality Complaint Citation Patent Citation
a system comprising: a charge bus configured to receive charging energy from a voltage source The accused vehicles include high voltage cables that receive energy from a charger via a charging inlet. ¶39 col. 4:18-24
an energy storage device configured to output a DC voltage and coupled to the charge bus The accused vehicles include a hybrid battery that outputs DC voltage and is coupled to the high voltage cables. ¶40 col. 4:5-8
a first bi-directional voltage modification assembly coupled to the charge bus The accused vehicles include a bi-directional DC/DC converter coupled to the high voltage cables. ¶41 col. 4:25-32
a controller configured to: monitor a transfer of the charging energy supplied to the energy storage device; compare the monitored transfer ... with a threshold ...; and after the threshold has been crossed, control the first bi-directional voltage modification assembly to modify one of a voltage and a current of the charging energy... The accused vehicles include a Battery Computer Assembly that monitors the transfer of energy to the battery. When the battery's voltage reaches a threshold (e.g., full charge), the controller causes the DC/DC converter to modify the voltage and current to stop charging. ¶42 col. 4:1-4; col. 4:33-41
  • Identified Points of Contention:
    • Scope Questions: The analysis may raise the question of whether the accused "Battery Computer Assembly" performs the specific three-step function (monitor, compare, control) recited in the claim. The complaint alleges the controller acts when the battery "reaches full charge," which raises the question of whether this meets the claim limitation of comparing the "transfer of charging energy" with a "threshold." (Compl. ¶42).
    • Technical Questions: A key technical question will be whether Toyota's "bi-directional DC/DC converter" is structurally and functionally equivalent to the claimed "bi-directional voltage modification assembly" as described in the patent's specification. The complaint supports this with a diagram from a Toyota manual identifying the "DC/DC converter." (Compl. p. 15).

U.S. Patent No. 8,086,364 Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
a method of energy management ... comprising: identifying a current location of a vehicle The accused vehicles identify the vehicle's current location using GPS. ¶53 col. 5:29-31
applying a pre-screening algorithm with respect to a link within a map and the current location, the pre-screening algorithm based on a maximum link length of a historical power-use database The accused vehicles' navigation system suggests destinations, such as charging stations when the battery is low, based on "various information, such as the current position, driving time, etc.," which allegedly corresponds to applying a pre-screening algorithm based on range estimates from historical power use. ¶54 col. 5:32-42
determining if one or more links are within a given bounds The accused vehicles determine if a road segment to a charging station is within the vehicle's estimated range. ¶55 col. 5:43-45
if one or more links are within a given bounds, then matching the current location of the vehicle to the link within the map via a subsequential matching algorithm The accused vehicles match the vehicle's current location to a link within the map via a subsequential matching algorithm, such as ranking charging stations by distance or charging time. ¶56 col. 5:46-50
if one or more links are within a given bounds, then uploading power information used by the vehicle along the link and at the current location into the historical power-use database The accused vehicles, via Toyota's Connected Services, collect and transmit vehicle data, including location and driving data, which allegedly constitutes uploading power information to a historical database. ¶57 col. 5:51-55
  • Identified Points of Contention:
    • Scope Questions: A central question will be whether the accused navigation system's "POI suggestion" feature, as described in the complaint, constitutes the claimed "pre-screening algorithm based on a maximum link length of a historical power-use database." (Compl. ¶54). The defense may argue that suggesting nearby points of interest is a generic navigation function, not the specific database-driven algorithm claimed.
    • Technical Questions: The complaint alleges that Toyota's collection of "vehicle's location, driving data ... and vehicle health information" for its "Connected Services" satisfies the "uploading power information" step. (Compl. ¶57; p. 27). This raises the evidentiary question of what specific "power information" is actually collected and whether it is stored and used in a manner that meets the definition of a "historical power-use database" as contemplated by the patent.

V. Key Claim Terms for Construction

For the ’884 Patent:

  • The Term: "bi-directional voltage modification assembly" (Claim 20)
  • Context and Importance: This is the core active component of the claimed system. The infringement allegation hinges on mapping this term to Toyota's "bi-directional DC/DC converter." (Compl. ¶41). Practitioners may focus on whether the patent's description limits this "assembly" to a specific structure or configuration that differs from the accused converter.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent describes the assembly as being able to "buck" or "boost" voltage, a common function of DC/DC converters. The specification also refers to it more generally as a "bi-directional DC-to-AC voltage inverter." (’884 Patent, col. 5:65-67).
    • Evidence for a Narrower Interpretation: The detailed figures show a specific arrangement of half-phase modules, inductors, and switches. (’884 Patent, FIG. 1). A defendant may argue that the term should be limited to the specific inverter topology disclosed in the preferred embodiments.

For the ’364 Patent:

  • The Term: "historical power-use database" (Claim 9)
  • Context and Importance: The use of this database is what distinguishes the claimed method from generic navigation. The infringement theory depends on showing that the data collected by Toyota for its "Connected Services" and used for "POI suggestion" constitutes such a database. (Compl. ¶¶54, 57).
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the database as storing "power, speed, and other performance information associated with each link." (’364 Patent, col. 6:33-36). Plaintiff may argue this broadly covers any collection of driving and location data used to inform energy-related suggestions.
    • Evidence for a Narrower Interpretation: The patent details a specific structure where the database links power usage to specific, uniquely identified road "links" defined by "start and end nodes." (’364 Patent, col. 6:1-6). A defendant may argue that a general collection of vehicle telematics does not constitute the structured, link-based database required by the patent.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement for all asserted patents. The basis for inducement is Defendant's alleged creation and dissemination of user manuals, marketing materials, and online instructional videos that allegedly "teach and encourage" customers to use the accused features (e.g., the charging function for the '884 patent, the navigation system for the '364 patent) in an infringing manner. (Compl. ¶¶43-44, 58-59, 74-75).
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents. The allegations are based on alleged pre-suit knowledge stemming from communications between Plaintiff's licensing agent and Defendant beginning in November 2024. The complaint specifically alleges that detailed claim charts demonstrating infringement for all nine asserted patents were provided to and downloaded by Toyota between August and November 2025, prior to the filing of the complaint. (Compl. ¶¶27-30, 46, 61).

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

  • A core issue will be one of definitional scope: Across multiple patents, the dispute may turn on whether generalized components in modern vehicles (e.g., a "DC/DC converter," a cloud-based "Connected Services" platform) can be construed to meet the specific functional and structural limitations of the claimed inventions (e.g., a "bi-directional voltage modification assembly," a "historical power-use database").
  • A second central question will be one of functional specificity: Does the accused software, such as Toyota's navigation system suggesting points of interest or its charging controller managing a full battery, perform the specific, multi-step logical processes required by the method claims, or is there a material difference in their technical operation?
  • A third key question will relate to willfulness: Given the complaint's detailed allegations of pre-suit notice, including the provision and downloading of specific claim charts, the development of facts surrounding these communications will be central to determining whether Defendant's alleged continued infringement was willful.