DCT
1:23-cv-01093
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: 1:23-cv-01093, W.D. Tex., 12/04/2023
- Venue Allegations: Venue is asserted based on Defendant Tesla residing and maintaining a regular and established place of business in the district, including its global headquarters.
- Core Dispute: Plaintiff alleges that Defendant’s Powerwall and Powerwall+ home energy storage systems, which include a Tesla Solar Inverter, infringe a patent related to managing power flow in a grid-tied photovoltaic system.
- Technical Context: The lawsuit concerns the technology of home energy systems that integrate solar panel power generation, battery storage, and connection to the main electrical grid, particularly how such systems manage power during grid outages.
- Key Procedural History: The complaint is a First Amended Complaint. Plaintiff alleges that Defendant has had knowledge of the patent-in-suit and the alleged infringement since at least September 15, 2023, the service date of the original complaint in this action. The complaint explicitly states it is not alleging pre-suit indirect infringement or 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 Filing Date |
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 the challenge of integrating distributed power generation, like residential solar panels, with the utility grid (U.S. Patent No. 9,793,755, col. 1:12-24). Specifically, it notes that while grid-tied solar inverters can send power to the grid, they typically cannot power a home during a grid outage. Furthermore, ensuring that these systems safely disconnect from a dead grid requires separate, costly voltage-frequency relays ('755 Patent, col. 1:30-41).
- The Patented Solution: The invention is a unified uninterruptible power supply (UPS) that acts as an intelligent hub between a battery, current-source inverters (like those connected to solar panels), the home's electrical load, and the utility grid ('755 Patent, Abstract). When the grid is down, the UPS can operate as a local AC voltage source, providing power from the battery. Crucially, it controls the power output from the solar inverters by adjusting the frequency of this local AC voltage, signaling the inverters to reduce or stop their output to prevent overcharging the battery ('755 Patent, col. 8:56-64; Fig. 6).
- Technical Importance: This design integrates backup power, grid-tie functionality, and safety features into a single device, aiming to reduce the cost and complexity of residential solar-plus-storage systems ('755 Patent, col. 2:5-11).
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 configured to be coupled to a current-source inverter.
- The current-source inverter is configured to adjust an output power as a function of a frequency of the alternating current voltage source.
- A controller configured to regulate a power flow of the current-source inverter by adjusting a frequency of the alternating current voltage source.
- The complaint states that Tesla infringes "one or more claims," suggesting the right to assert other claims, including dependent claims, is reserved (Compl. ¶12).
III. The Accused Instrumentality
Product Identification
- The "Accused Instrumentalities" are identified as Tesla's home backup systems, specifically the Powerwall (fka Powerwall 2) and Powerwall+ systems, which include a Tesla Solar Inverter (Compl. ¶12).
Functionality and Market Context
- The complaint alleges that the accused systems are rechargeable home batteries that store energy from solar panels and can provide backup power during a grid outage (Compl. p. 4). A key accused function is the "Go Off-Grid" mode, which allows a user to manually disconnect from the utility grid (Compl. ¶22). In this mode, or during an actual outage, the system performs "Solar Curtailment" to manage excess solar production when the battery is full. This is allegedly accomplished by having the Powerwall "raise your system frequency to turn off your solar inverter" to prevent overcharging or system damage (Compl. ¶22, 30). The complaint includes a screenshot from Tesla's website describing this "Solar Curtailment" functionality (Compl. p. 8, 12). Tesla's marketing materials, cited in the complaint, promote this functionality for "Backup Energy Storage" and "Outage Protection" (Compl. ¶26). A screenshot from the Tesla app shows the step-by-step instructions for a user to "Take Me Off-Grid" (Compl. p. 9).
IV. Analysis of Infringement Allegations
The complaint references an attached claim chart (Exhibit B) that was not included in the publicly filed document (Compl. ¶16). The following analysis is based on the narrative allegations and visual evidence within the complaint body.
'755 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An uninterruptible power supply comprising: a bi-directional converter configured to operate as an alternating current voltage source; | The Tesla Powerwall and Powerwall+ systems, which operate as a voltage source to power a home when in "Go Off-Grid" mode or during a grid outage. | ¶12, 25 | col. 8:9-10 |
| a direct current power port configured to be coupled to a battery; | The internal connection within the Powerwall system between its converter and its integrated rechargeable battery. | ¶12, 14 | col. 6:38-40 |
| a first alternating current power port coupled to the bi-directional converter and configured to be coupled to a current-source inverter, | The connection between the Powerwall system and the Tesla Solar Inverter. | ¶12, 14 | col. 6:43-47 |
| wherein the current-source inverter is configured to adjust an output power as a function of a frequency of the alternating current voltage source; and | The Tesla Solar Inverter, which is alleged to be a current-source inverter that turns off, thereby adjusting its output power, in response to a raised system frequency. | ¶30, 35 | col. 6:5-10 |
| 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's controller, which, during "Solar Curtailment," allegedly "raise[s] [the] system frequency to turn off your solar inverter" to regulate power flow and prevent overcharging the battery. | ¶22, 30 | col. 9:56-62 |
- Identified Points of Contention:
- Scope Questions: The complaint alleges the Tesla Solar Inverter is a "current-source inverter" as required by the claim (Compl. ¶12, 14). The case may turn on whether the technical characteristics of the Tesla Solar Inverter fall within the scope of the term "current-source inverter" as it is defined and used within the '755 patent.
- Technical Questions: Claim 1 requires a controller that "regulate[s] a power flow... by adjusting a frequency." The complaint alleges infringement occurs when the accused system "raise[s] [the] system frequency to turn off your solar inverter" (Compl. ¶30). A central question will be whether this binary "turn off" action constitutes "regulat[ing] a power flow" as contemplated by the patent, which also describes using frequency to reduce power for trickle-charging (col. 8:60-64), suggesting a more nuanced level of control.
V. Key Claim Terms for Construction
- The Term: "current-source inverter"
- Context and Importance: This term is critical because infringement requires the accused Tesla Solar Inverter to be a "current-source inverter." The definition will determine whether the accused system's architecture meets the claim limitations. Practitioners may focus on this term because the patent's description primarily discusses "micro-inverters" and "grid-tied inverters" generally, and the specific technology of the accused inverter will be scrutinized against that description.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent background states that "Grid-tied inverters act as a current source" ('755 Patent, col. 1:42-43). This could support an argument that the term encompasses a wide range of inverters designed to feed power to an AC grid, including the accused Tesla Solar Inverter.
- Evidence for a Narrower Interpretation: The patent specification repeatedly references "micro-inverters" when discussing examples of current-source inverters ('755 Patent, col. 5:4-15, col. 5:25-36). An argument could be made that the term should be limited to the specific type of inverter technology emphasized in the patent's examples.
- The Term: "regulate a power flow ... by adjusting a frequency"
- Context and Importance: This limitation defines the core control mechanism of the invention. The dispute will likely center on the meaning of "regulate." Whether Tesla's "turn off" functionality (Compl. ¶30) is considered "regulation" will be a pivotal issue.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent describes using frequency adjustment to achieve different outcomes, including allowing "maximum power flow" and reducing power flow until the battery is "trickle-charged" ('755 Patent, col. 8:56-64). This suggests "regulate" encompasses a range of control actions, from full power to very low power, which could include turning the inverter off entirely to stop power flow.
- Evidence for a Narrower Interpretation: The description of "trickle-charg[ing]" ('755 Patent, col. 8:64) could imply that "regulate" requires a fine-tuned, continuous, or proportional control over power, rather than a simple on/off switching mechanism triggered by a frequency shift.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement based on post-suit knowledge. It asserts that since being served with the original complaint, Tesla has continued to provide instructions, user manuals, and technical support on its website that encourage and direct customers to use the accused "Go Off-Grid" and "Solar Curtailment" features in a manner that allegedly infringes the '755 patent (Compl. ¶¶17-24). The complaint also pleads contributory infringement, alleging the Tesla Solar Inverter is a material component specially made for infringing use and is not a staple article of commerce with substantial non-infringing uses (Compl. ¶¶32-35).
- Willful Infringement: Plaintiff explicitly disclaims any allegation of pre-suit willfulness (Compl. p. 16, fn. 2). However, the allegations of continued infringement after receiving the original complaint on September 15, 2023, could form the basis for a later claim of post-filing willfulness (Compl. ¶18).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim construction and scope: Can the term "current-source inverter", as used in the context of the patent's disclosure, be construed to read on the specific technology of the accused Tesla Solar Inverter?
- A second pivotal question will be one of functional operation: Does the accused system's "Solar Curtailment" feature, which allegedly raises frequency to turn off the solar inverter, meet the claim limitation of "regulat[ing] a power flow... by adjusting a frequency," or does the patent require a more nuanced, proportional control that creates a technical mismatch?
- A key evidentiary question for indirect infringement will be whether intent can be inferred: Do Tesla's publicly available user manuals and website instructions, maintained post-suit, provide sufficient evidence to demonstrate a specific intent to encourage its customers to perform the allegedly infringing acts?