DCT

1:20-cv-00849

NEXTracker Inc v. Solar Flexrack

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:20-cv-00849, D. Del., 06/25/2020
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant Northern States Metals Company is incorporated in Delaware.
  • Core Dispute: Plaintiff alleges that Defendant’s solar tracker systems infringe two patents related to the mechanical support and rotation structures for solar panels.
  • Technical Context: The technology concerns single-axis solar trackers, which are large-scale mechanical systems designed to rotate rows of solar panels to follow the sun, maximizing energy capture.
  • Key Procedural History: The complaint alleges that Plaintiff sent a letter to Defendant on May 7, 2020, providing notice of the '669 Patent and Defendant's alleged infringement, prior to filing the lawsuit.

Case Timeline

Date Event
2012-12-10 '686 Patent Priority Date
2014-11-05 '669 Patent Priority Date
2017 FlexRack introduces its “TDP-2.0” tracker system
2017-10-31 U.S. Patent No. 9,806,669 Issue Date
2018-05-15 U.S. Patent No. 9,970,686 Issue Date
2020-05-07 NEXTracker sends notice letter to FlexRack regarding the '669 Patent
2020-06-25 Complaint Filing Date

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

U.S. Patent No. 9,806,669 - "Single-Axis Follower Support System for a Solar Collector," issued October 31, 2017

The Invention Explained

  • Problem Addressed: The patent describes a problem in prior art solar trackers where the horizontal axis of rotation is located a significant distance from the center of gravity of the solar panel assembly. This offset requires greater effort and energy to rotate the panels ('669 Patent, col. 1:56-62).
  • The Patented Solution: The invention proposes a bearing system that brings the axis of rotation closer to the panels' center of gravity. It achieves this with a two-part bearing: a rotatable part that holds the main support beam and features a curved guide rail underneath, and a fixed base with rolling members that travel within that guide rail. This configuration allows the support beam to sit lower relative to the rotation point, reducing torque requirements ('669 Patent, Abstract; col. 2:4-24).
  • Technical Importance: This design sought to reduce the mechanical load and energy consumption of large-scale solar tracking systems, potentially lowering operational costs and improving long-term reliability ('669 Patent, col. 1:56-62).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶26).
  • The essential elements of independent claim 1 are:
    • A fixed structure for anchorage to a ground.
    • A platform for supporting a solar collector, fastened to a horizontal central beam that is rotatably mounted on the fixed structure.
    • At least one bearing that comprises:
      • (i) a rotatable part with a housing for the beam and a circular-arch shaped guide rail below the housing.
      • (ii) a base held on the fixed structure with fastened rolling members that are mounted to roll in the guide rail of the rotatable part.
  • The complaint alleges infringement of "at least claim 1," reserving the right to assert other claims (Compl. ¶26).

U.S. Patent No. 9,970,686 - "Balanced Solar Tracker Clamp," issued May 15, 2018

The Invention Explained

  • Problem Addressed: The patent addresses the general inadequacy of conventional solar tracking mechanisms and the desirability of improving solar systems ('686 Patent, col. 1:19-23). The abstract and summary suggest a focus on aligning the system's center of mass with its center of rotation to reduce the load on the drive motor ('686 Patent, Abstract).
  • The Patented Solution: The invention describes a tracker apparatus with specific structural components designed for stability and ease of installation. A key component is a clamp assembly with a housing that couples to the main torque tube. This housing has a uniquely shaped opening with a "first inner region" and a "second inner region" that act as mechanical stops to limit the rotational movement of the torque tube in two different radial directions, thereby controlling the panel's range of motion ('686 Patent, col. 12:46-56).
  • Technical Importance: This design aims to provide a robust, balanced solar tracker that can be assembled with high tolerance for construction variances and that precisely controls the rotational forces on the torque tube ('686 Patent, col. 5:1-3).

Key Claims at a Glance

  • The complaint asserts independent claim 8 (Compl. ¶45).
  • The essential elements of independent claim 8 are:
    • A first pier with a first pivot device.
    • A second pier with a drive mount capable of accommodating construction tolerances in at least three axes.
    • A torque tube operably disposed on the piers.
    • A clamp configured around the torque tube to support a solar module.
    • A clamp assembly with a housing coupled to the torque tube, where the housing has an opening with first and second inner regions that act as first and second stops for the torque tube's movement in first and second radial directions, respectively.
  • The complaint alleges infringement of "at least claim 8," reserving the right to assert other claims (Compl. ¶45).

III. The Accused Instrumentality

Product Identification

  • The accused product is the "TDP-2.0" solar tracker system, which Defendant Solar FlexRack ("FlexRack") allegedly designs, manufactures, uses, sells, and offers for sale (Compl. ¶¶15-16).

Functionality and Market Context

  • The TDP-2.0 is a single-axis solar tracker system used to rotate photovoltaic modules to increase power production (Compl. ¶1). The complaint alleges it is a direct competitor to Plaintiff's products (Compl. ¶15).
  • FlexRack allegedly offers the TDP-2.0 system throughout the United States and markets it at industry conferences (Compl. ¶¶17-18). A map in the complaint shows the locations of FlexRack's solar tracker installations (Compl. ¶17).
  • The system is allegedly sold both as a complete, installable tracker and as a "collection of components" for customers to assemble (Compl. ¶19).

IV. Analysis of Infringement Allegations

  • ’669 Patent Infringement Allegations
Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a fixed structure for anchorage to a ground The TDP-2.0 solar trackers contain vertical piers that are fixed to and provide anchorage to the ground. ¶28 col. 4:21-24
a platform configured to support at least one solar collector, said platform being fastened on at least one horizontal central beam rotatably mounted on the fixed structure around a horizontal axis of rotation inside at least one bearing fastened on the fixed structure The TDP-2.0 solar trackers have a platform for solar collectors fastened to a horizontal central beam, which is rotatably mounted on the fixed piers via a bearing. An annotated screenshot in the complaint identifies the platform, bearing, and horizontal beam of the accused product. (Compl. p. 9). ¶29 col. 4:31-38
wherein at least one bearing comprises (i) a rotatable part including, on the one hand, a housing for receiving the horizontal central beam and, on the other hand, a guide rail presenting a circular-arch shape... said guide rail extending below said housing The TDP-2.0 trackers allegedly contain a bearing with a rotatable part that includes a housing for the beam and a curved guide rail below it. ¶30 col. 2:17-21
and (ii) a base held on the fixed structure and onto which are fastened rolling members, said rolling members being mounted so as to roll in the guide rail of the rotatable part The TDP-2.0 trackers allegedly have a base held on the pier with fixed rolling members that are mounted to roll in the guide rail. A side-by-side comparison image shows the accused product's bearing assembly next to a figure from the '669 Patent, with components like the Rotatable Part, Guide Rail, Housing, Base, and Fixed Rolling Members labeled on the accused product. (Compl. p. 10). ¶30 col. 2:22-24
  • ’686 Patent Infringement Allegations

| Claim Element (from Independent Claim 8) | Alleged Infringing Functionality - | Complaint Citation | Patent Citation |
|:--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |:-----------------------|:--------------------|
| a first pier comprising a first pivot device - | The TDP-2.0 trackers contain a first pier with a pivot device. - | ¶47 | col. 3:66-67 |
| a second pier comprising a drive mount, the drive mount capable of accommodating construction tolerances in at least three-axes - | The TDP-2.0 trackers contain a second pier with a drive mount. A visual comparison between the accused product and '686 Patent Figure 15 is provided to support this allegation. (Compl. p. 13). - | ¶48 | col. 5:1-3 |
| a torque tube operably disposed on the first pier and the second pier, the torque tube comprising a first end and a second end - | The TDP-2.0 trackers contain a torque tube that is disposed on the first and second piers. - | ¶49 | col. 5:5-7 |
| a clamp configured around a portion of the torque tube, the clamp comprising a support region configured to support a portion of a solar module - | The TDP-2.0 trackers have a clamp configured around the torque tube that supports a solar module. - | ¶50 | col. 5:11-14 |
| a clamp assembly comprising a housing coupled to the torque tube... the housing comprising an opening having a major plane normal to a length of the torque tube, the opening comprising a first inner region and a second inner region, the first inner region acts as a first stop... and the second inner region acts as a second stop... | The TDP-2.0 trackers allegedly have a clamp assembly with a housing containing an opening with two inner regions that act as stops for the torque tube's movement in two radial directions. The complaint includes a detailed, annotated image of the accused clamp assembly identifying the housing, opening, first and second inner regions, and major plane. (Compl. p. 16). | ¶51 | col. 14:7-12 |

  • Identified Points of Contention:
    • Scope Questions: For the ’669 Patent, a question may arise regarding the scope of "rolling members being mounted so as to roll in the guide rail." The defense may contest whether the interaction in the accused device constitutes "rolling" in the manner claimed, or if the components are structurally distinct.
    • Technical Questions: For the ’686 Patent, the infringement analysis may focus on the functional language of claim 8. A key question will be whether the "first inner region" and "second inner region" of the accused housing are configured to, and in fact do, function as "stops" for "radial" movement, as opposed to serving a different primary purpose such as alignment or support.

V. Key Claim Terms for Construction

For the ’669 Patent:

  • The Term: "rolling members being mounted so as to roll in the guide rail" (Claim 1)
  • Context and Importance: This phrase defines the central mechanism of the claimed bearing. The interpretation of "roll in" will be critical. Practitioners may focus on this term because the specific nature of this claimed movement and interaction between the fixed and rotatable parts of the bearing is a primary point of novelty. The defense could argue that the interaction in the accused device is sliding, guiding, or another form of contact that does not meet the "rolling" limitation.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification suggests some flexibility by stating the rolling members can be of the "ball bearing type, needle bearing type or roller bearing type" (’669 Patent, col. 3:27-30), which covers various forms of rolling elements.
    • Evidence for a Narrower Interpretation: The figures, such as FIG. 2 and FIG. 5, depict a specific arrangement where rolling members (8) are "caged or enclosed" between lateral elements (70) and travel within a defined slot (51), which may be used to argue for a more constrained structural meaning (’669 Patent, col. 3:1-3).

For the ’686 Patent:

  • The Term: "drive mount capable of accommodating construction tolerances in at least three-axes" (Claim 8)
  • Context and Importance: This term is critical because it relates to the practical installability and alignment of the tracker system, a key real-world feature. Practitioners may focus on this term because the defense may argue that their drive mount does not provide adjustability in three distinct axes as described, or that any such accommodation is achieved through a mechanism different from what the patent discloses.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself is functional and does not specify a particular structure for achieving the three-axis accommodation, potentially allowing for a range of mechanisms.
    • Evidence for a Narrower Interpretation: The specification describes achieving adjustability through a "spherical bearing" which "allows for a construction tolerance" and movement (’686 Patent, col. 6:20-23; col. 11:10-13). An opponent could argue this ties the claim to embodiments that rely on such a bearing. Further, Figures 21-27 depict specific adjustments (vertical, lateral, rotational) which could be used to define the scope of the required "three-axes."

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for both patents.
    • Inducement: The allegations are based on FlexRack’s marketing, including its website and YouTube channel, and its provision of services like "engineering, geotechnical analysis, pull-testing, field and layout services," which allegedly instruct and encourage customers to install and use the accused TDP-2.0 system in an infringing manner (Compl. ¶¶ 20-22, 36, 57).
    • Contributory Infringement: This claim is based on allegations that FlexRack sells the TDP-2.0 system as a "collection of components" that are "especially made or adapted for use in an infringing manner" and are not staple articles of commerce with substantial non-infringing uses (Compl. ¶¶ 32-33, 53-54).
  • Willful Infringement:
    • For the ’669 Patent, the complaint alleges pre-suit knowledge based on a notice letter sent on May 7, 2020, and FlexRack's subsequent refusal to "take a license or stop marketing and selling the infringing TDP-2.0 tracker system" (Compl. ¶¶ 23, 39).
    • For the ’686 Patent, the complaint alleges knowledge "at least as of the filing of this complaint," which supports a claim for post-suit willful infringement (Compl. ¶60).

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

  • A central issue will be one of structural and functional correspondence: Will the court find that the accused TDP-2.0's bearing and clamp assemblies contain structures that perform in substantially the same way to achieve substantially the same results as the specific mechanisms recited in the asserted claims? This will require a granular comparison of the accused product's mechanics against the claim language.
  • A key legal question will be one of claim construction: How will the court define the scope of key terms such as "to roll in the guide rail" (’669 Patent) and the functional requirement that specific inner regions "act as a... stop" for radial movement (’686 Patent)? The outcome of these definitions will likely determine infringement.
  • Finally, a key evidentiary question will concern knowledge and intent: Can NEXTracker prove that FlexRack's conduct, particularly after receiving the May 2020 notice letter, rose to the level of willful infringement or inducement? The evidence surrounding FlexRack's awareness and actions will be critical for these allegations.