DCT
3:25-cv-03365
Relink US LLC v. Tesla Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Relink US LLC (Texas)
- Defendant: Tesla, Inc. (Delaware)
- Plaintiff’s Counsel: Bunsow De Mory LLP; George Brothers Kincaid & Horton, L.L.P.
- Case Identification: Relink US LLC v. Tesla, Inc., 1:23-cv-01093, W.D. Tex., 12/04/2023
- Venue Allegations: Venue is asserted based on Defendant’s headquarters, regular and established places of business, and substantial employee presence within the Western District of Texas.
- Core Dispute: Plaintiff alleges that Defendant’s Powerwall and Powerwall+ home energy storage systems, when used with a Tesla Solar Inverter, infringe a patent related to managing power flow in grid-tied solar power systems.
- Technical Context: The technology concerns integrated power management systems that provide both grid-connected and off-grid backup functionality for residential solar installations, a key feature in the growing market for energy independence and resilience.
- Key Procedural History: The complaint is a First Amended Complaint, superseding an original complaint served on September 15, 2023. Plaintiff notes that one of its managing members and a named inventor on the patent-in-suit, Mr. Paul Garrity, is also the inventor on numerous other patents assigned to Defendant, suggesting Defendant’s familiarity with the inventor’s work. Plaintiff explicitly disclaims allegations of pre-suit willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 2015-07-28 | ’755 Patent Priority Date |
| 2017-10-17 | ’755 Patent Issue Date |
| 2023-09-15 | Original Complaint Served on Defendant |
| 2023-12-04 | First Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,793,755 - "Uninterruptible Power Supply and Method for Managing Power Flow in a Grid-Tied Photovoltaic System," issued October 17, 2017
The Invention Explained
- Problem Addressed: The patent describes challenges in the field of distributed solar power, including grid instability, the high cost of separate components for grid-tie and backup power functions, and the need for expensive, separate voltage-frequency relays to ensure safety during grid outages (’755 Patent, col. 1:24-40).
- The Patented Solution: The invention is an integrated uninterruptible power supply (UPS) that combines multiple functions into a single system. It uses a central bi-directional converter and a controller to manage power flow between a battery, solar inverters (described as "current-source inverters"), the local electrical load, and the utility grid (’755 Patent, Abstract; Fig. 3). When the grid fails, the system can disconnect and operate as a standalone "voltage source" to power the home; when connected, it can act as a "current source" to manage power exchange with the grid, including leveling peak loads (’755 Patent, col. 2:50-65). A key feature is the ability to control the power output of the solar inverters by adjusting the frequency of the local AC power it generates, eliminating the need for a separate relay (’755 Patent, col. 6:58-65).
- Technical Importance: This integrated approach was designed to reduce the overall cost and complexity of residential solar systems while adding sophisticated capabilities like backup power and grid-stabilizing functions, which were typically found only in separate, expensive, or utility-scale systems (’755 Patent, col. 1:56-59).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 1 (Compl. ¶15).
- Independent Claim 1 requires:
- A bi-directional converter configured to operate as an alternating current voltage source.
- A direct current power port configured to be coupled to a battery.
- A first alternating current power port coupled to the bi-directional converter and a current-source inverter, where the inverter adjusts its output power based on the frequency of the voltage source.
- A controller that regulates the power flow from the current-source inverter by adjusting the frequency of the alternating current voltage source.
- The complaint does not explicitly reserve the right to assert dependent claims, but the prayer for relief seeks judgment for infringement of "one or more claims" (Compl. ¶A, p.15).
III. The Accused Instrumentality
Product Identification
- The "Accused Instrumentalities" are identified as Tesla's home backup systems that include a Tesla Solar Inverter, specifically the Powerwall (fka Powerwall 2) and Powerwall+ systems (Compl. ¶12).
Functionality and Market Context
- The complaint alleges the Accused Instrumentalities are integrated systems for home energy management. The Powerwall is described as a rechargeable home battery, while the Powerwall+ integrates the battery with a Tesla Solar Inverter and a system controller (Compl. p. 4). The Tesla Solar Inverter converts energy from solar panels for use by the home, and the system can store excess solar energy in the battery for backup protection during grid outages (Compl. p. 4, 11).
- A key accused feature is the "Go Off-Grid" mode, which allows a user to disconnect the system from the utility grid to simulate an outage (Compl. ¶22). In this mode, or during an actual outage, the system allegedly performs "Solar Curtailment" to prevent overcharging the battery. The complaint includes a screenshot from Tesla's website that describes this functionality. (Compl. p. 8). This screenshot states that to prevent overcharging when off-grid, "your Powerwall will raise your system frequency to turn off your solar inverter" (Compl. p. 8, 12). The complaint alleges this functionality is central to the infringement and is marketed as a key feature for "Backup Energy Storage" and "Outage Protection" (Compl. p. 10). A visual from Tesla's website shows the Powerwall marketed with icons for "Backup Energy Storage," "24/7 Outage Protection," and "Energy Independence" (Compl. ¶26, p. 10).
IV. Analysis of Infringement Allegations
9,793,755 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a bi-directional converter configured to operate as an alternating current voltage source | The Powerwall and Powerwall+ systems operate as a voltage source to supply power to the home when disconnected from the grid, such as during an outage or in "Go Off-Grid" mode. | ¶12, 27 | col. 6:1-3 |
| a direct current power port configured to be coupled to a battery | The Powerwall and Powerwall+ systems are rechargeable home battery systems. | ¶12 | col. 6:3-4 |
| a first alternating current power port coupled to the bi-directional converter and configured to be coupled to a current-source inverter, wherein the current-source inverter is configured to adjust an output power as a function of a frequency of the alternating current voltage source | The Tesla Solar Inverter is coupled to the Powerwall system and is allegedly turned off (i.e., its power is adjusted) in response to a frequency increase from the Powerwall. | ¶12, 30, 33 | col. 6:4-9 |
| a controller configured to regulate a power flow of the current-source inverter by adjusting a frequency of the alternating current voltage source | The Powerwall controller allegedly raises the system frequency specifically "to turn off your solar inverter" to prevent the battery from overcharging when the system is off-grid and the battery is full. | ¶30 | col. 8:58-65 |
- Identified Points of Contention:
- Scope Questions: A central question may be whether the "Tesla Solar Inverter" component meets the claim definition of a "current-source inverter." The patent distinguishes between current-source (grid-tied) and voltage-source (stand-alone) inverters (’755 Patent, col. 1:41-48). The court may need to determine if the accused inverter operates in the manner contemplated by the patent.
- Technical Questions: Does the accused "Solar Curtailment" feature, which "turn[s] off" the solar inverter by raising frequency, perform the claimed function of "regulat[ing] a power flow"? (Compl. ¶30). A court may examine whether this on/off function is equivalent to the "regulation" described in the patent, which contemplates a potentially more nuanced control of power (’755 Patent, col. 6:30-35). Additionally, the architectural mapping of the accused system to the claimed components (e.g., is the Powerwall a "bi-directional converter" or a more complex system?) may be a point of dispute.
V. Key Claim Terms for Construction
The Term: "current-source inverter"
- Context and Importance: This term is critical because the infringement theory hinges on the Tesla Solar Inverter being a "current-source inverter" whose power output is controlled by the Powerwall's frequency adjustments. The definition will determine if the architecture of the accused system maps to the claims.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent’s background describes "grid-tied inverters" as acting as a "current source" (’755 Patent, col. 1:42-43). Plaintiff may argue that any grid-forming solar inverter that responds to frequency shifts falls within this definition.
- Evidence for a Narrower Interpretation: The patent specifically discusses micro-inverters and string inverters as examples of current-source inverters designed to limit power when grid frequency varies (’755 Patent, col. 6:28-35). Defendant may argue the term is limited to inverters that exhibit the specific linear power reduction behavior described in the specification, rather than a simple shut-off.
The Term: "regulate a power flow... by adjusting a frequency"
- Context and Importance: Practitioners may focus on this term because the core of the infringement allegation is that Tesla's "Solar Curtailment" feature embodies this function. The dispute will likely center on whether "turn[ing] off" an inverter constitutes "regulating" power flow in the manner claimed.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent states the controller "adjusts the frequency... to cause the micro-inverters... to reduce their power output" (’755 Patent, col. 8:60-63). Plaintiff may argue that reducing power to zero (i.e., turning it off) is the ultimate form of reduction and thus falls within the claim's scope.
- Evidence for a Narrower Interpretation: The specification describes a system designed to "linearly decrease their power output from 100% to 40% when the frequency increases from 50.2 Hz to 50.5 Hz" (’755 Patent, col. 6:31-34). Defendant may argue that "regulate" requires this type of proportional or modulated control, not a binary on/off switching action.
VI. Other Allegations
- Indirect Infringement: The complaint places significant emphasis on induced infringement. It alleges Tesla intentionally instructs customers to infringe by providing detailed online documentation, support pages, and manuals for features like "Go Off-Grid" (Compl. ¶¶19, 23). The complaint cites and provides a screenshot of step-by-step instructions for activating the "Go Off-Grid" mode, alleging these instructions show affirmative intent for the product to be used in an infringing manner (Compl. ¶24, p. 9). The complaint also alleges contributory infringement, asserting the Tesla Solar Inverter is a material component especially made for infringing use with no substantial non-infringing uses, as its operation to "prevent overcharging" is necessary in any mode (Compl. ¶¶33, 35).
- Willful Infringement: The complaint does not allege pre-suit willfulness (Compl. p. 16, fn. 2). It alleges that Tesla has had knowledge of the ’755 patent and its alleged infringement since at least the service of the original complaint on September 15, 2023, and that subsequent infringing conduct is therefore willful (Compl. ¶¶17-18).
VII. Analyst’s Conclusion: Key Questions for the Case
The resolution of this dispute may depend on the court’s answers to several central questions:
- A core issue will be one of technical mapping: Does the architecture of the Tesla Powerwall, Powerwall+, and Solar Inverter system, as a whole, correspond to the patent's more delineated structure of a "bi-directional converter" coupled to a separate "current-source inverter", or is there a fundamental structural mismatch?
- A key question of claim scope will be whether the accused system’s function of "turn[ing] off" the solar inverter via a frequency increase falls within the scope of "regulat[ing] a power flow" as that term is used in the patent, which describes a more graduated power reduction in its preferred embodiments.
- Finally, an evidentiary question will center on inducement: Does Tesla’s marketing and instructional material for its "Go Off-Grid" and "Solar Curtailment" features demonstrate a specific intent to encourage users to operate the system in a manner that performs every step of the claimed method?