Intellectual Property Law Representation

Shoals Technologies’ Patents on Connecting Solar Panels Asserted at the ITC

by | Oct 7, 2024 | Green IP

On August 30, 2024, the United States International Trade Commission (“ITC”) issued a Notice of Final Initiation Determination, finding that defendants Voltage, LLC and Ningbo Voltage Smart Production Co. violated certain claims in U.S. Patent No. 11,689,153, assigned to Shoals Technologies Group, LLC (“Shoals Technologies”).  In the Matter of Certain Photovoltaic Connectors and Components Thereof, Inv. No. 337-TA-1365, Doc. ID. 832409 (ITC Aug. 30, 2024).

This case initially involved three patents relating to solar technology.  According to one of the patents, conventional solar installations may include multiple solar panels connected to each other, forming a solar panel array.  Multiple arrays may, in turn, be electrically coupled to a central combiner box, and multiple combiner boxes may be electrically coupled to a central recombiner box.  U.S. Patent No. 10,553,739 (details below), Abstract; see also id., Fig. 1.

The three Shoals Technologies patents involved in the ITC case above purportedly simplify the conventional way to connect solar panels to each other.  Details below.

U.S. Patent No. 10,553,739 (“the ’739 patent”)

The ’739 patent, titled “Photovoltaic in Line Fuse Connector Assembly Having an Integral Fuse,” provides an assembly that can be integrated into solar panel arrays, where one fuse is integrated into each solar panel.  The ’739 patent at Abstract.

Conventional solar installations include a plurality of solar panels that are interconnected by a wire harness to form an array, each array using one fuse:

The ’739 patent, Fig. 1 (annotated).  In this conventional solar installation, tripping one circuit shuts down the operation of all the panels in the array, even if the circuit was tripped due to the malfunction of only one solar panel.  The ’739 patent at 1:33-37.

The purported solution of the ’739 patent is a photovoltaic in line connector assembly having fuses that are integrated into the harness, such that each solar panel has its own fuse:

The ’739 patent, Fig. 3 (annotated).

In this configuration, according to the ’739 patent, a malfunction in an individual panel will trip only the associated fuse, thereby allowing other panels in the array to function normally.  The ’739 patent at 2:60-63.

Conventional configuration The ’739 patent configuration
The ’739 patent, Fig. 2 (partial). The ’739 patent, Fig. 4 (partial).

The initial state of production of the photovoltaic in line connector assembly includes a fuse 15 connected at both ends to jumper wires 20, with one jumper wire connected to connector socket 45, and the other jumper wire connected to connector pin 35.  The ’739 patent at 3:1-5.

The ’739 patent, Fig. 6 (annotated).

A completed assembly may include a female connector 40, a male connector 30, and overmold 60.  The ’739 patent at 2:64-66.

The ’739 patent, Fig. 5 (annotated).  The assembly may include zero, one, or two connectors that are male, female, or one of each.  The ’739 patent, Abstract.

Further, the assembly is double molded to provide electrical insulation, protection, and strain relief.  The ’739 patent at 1:53-54.  According to the ’739 patent, the photovoltaic in line connector assembly allows for circuit protection to be moved from the combiner box to the wireless harness, thereby reducing cost by reducing the number of combiner boxes required in a solar field.  Id. at 1:55-62.

The assembly may be installed into each branch of a wire harness to provide the required over current protection.  The ’739 patent at 4:1-3.

The ’739 patent, Fig. 14.

Claim 1 of the ’739 patent recites:

       An in line assembly for a solar installation including:

  1. A photovoltaic fuse having a solid outer surface including a first end, a second end and a middle section there between, said solid outer surface defining an outline;
  2. An undermold surrounding and sealing said fuse, said undermold defining an outer surface outline, wherein the outer surface outline of said undermold is substantially parallel relative to the outline of said solid outer surface;
  3. An overmold defining an outline and surrounding said undermold, said undermold and said overmold each constructed of a single unit and each constructed of dissimilar materials, wherein the outline of said overmold is substantially parallel relative to the outline of said undermold; and
  4. A first photovoltaic connector engaged with said first end, wherein said assembly provides electrical insulation.

The ’739 patent, 4:28-45.

U.S. Patent No. 10,992,254 (“the ’254 patent”)

The ’254 patent, titled “Lead Assembly for Connecting Solar Panel Arrays to Inverter,” provides assemblies for connecting solar panel arrays to an inverter without a combiner box.  The ’254 patent, Abstract.

According to the ’254 patent, in the conventional solar installation, each array has a single input into the combiner box 36 through a wire harness 34.  The ’254 patent at 1:32-34.  The combiner box is, in turn, connected to an inverter 38, which converts the direct current (DC) generated by the solar panels into alternating power (AC).  Id. at 1:20-25; see also id. at 4:29 (introducing inverter 38).

The ’254 patent, Fig. 2 (labels repositioned; annotated).

The combiner boxes combine the energy coming from solar arrays.  Combiner boxes have been a necessary component in conventional solar installations, but they are purportedly expensive to install, maintain, troubleshoot, and move.  The ’254 patent at 1:39-49.

The purported solution of the ’254 patent replaces the combiner box with an assembly (such as lead assembly 10 in the figure below).

The ’254 patent, Fig. 3 (labels repositioned; annotated).  As shown above, one lead assembly 10 can accommodate multiple solar arrays.  Id. at 4:40-42.

The assembly includes at least one drop line 12 joined to a feeder cable 14 at a compression lug 20.  The ’254 patent at 1:58-59.

The ’254 patent, Fig. 7 (labels repositioned; annotated).

The ’254 patent, Fig. 8 (labels repositioned; annotated).

The drop line 12 is connected to solar arrays 32 via a drop line connector 13, while the feeder cable 14 is connected to an inverter 38 via a feeder cable connector 15.  Alternatively, the feeder cable is connected to a trunk buss jumper 27, which connects to the inverter 38.  The ’254 patent at 1:58-64.

The ’254 patent, Fig. 9 (labels repositioned; annotated).

According to the ’254 patent, lead assembly 10 effectively “combines” the power from solar arrays 32 and delivers it to inverter 38, thereby eliminating the need for a combiner box and DC feeders.  Lead assembly 10 also eliminates the need for fuses (discussed more in the ’739 patent above) by using drop lines.  The ’254 patent at 6:8-17.

Claim 1 of the ’254 patent recites:

      A lead assembly for use in a solar energy installation including:

  1. A first drop line and a second drop line, said first drop line terminating in a drop line connector;
  2. At least one 30 amp feeder cable terminating in a feeder cable connector, said first drop line and said at least one feeder cable electrically coupled at a nexus;
  3. A means for securing said nexus, said securing means selected from the group consisting of compression lug, soldering, splicing, crimping, and combinations thereof;
  4. An undermold having an inner surface and an outer surface, both surfaces extending in a longitudinal direction of said at least one feeder cable, said inner surface surrounding and fully encasing said securing means, said inner surface comprised of a first aperture concentric with said securing means and said at least one feeder cable, said first aperture extending continuously through said undermold in said longitudinal direction and having a first diameter, said at least one feeder cable continuously extending through said first aperture, and a second aperture concentric with said first drop line and parallel to said first aperture, said second aperture only partially extending through said undermold in said longitudinal direction, said second aperture having a second diameter smaller than said first diameter, said first drop line extending from said second aperture; and
  5. An overmold surrounding said undermold and forming an undermold-overmold interface only at said outer surface, wherein said lead assembly combines power from a plurality of solar arrays and transmits that power to an inverter in a solar energy installation lacking a combiner box between said solar arrays and said inverter, and wherein said lead assembly has a voltage rating of 1500 VDC.

The ’254 patent, 6:43-7:12.

U.S. Patent No. 11,689,153 (“the ’153 patent”)

The ’153 patent is a continuation of the ’254 patent, and is directed to a lead assembly including at least one drop line joined to a feeder cable at a nexus 19.  Recall that in the ’254 patent (discussed above), the drop line and feeder are joined at a compression lugCompare the ’153 patent at 1:63-65 to the ’254 patent at 1:58-59.

The ’153 patent, Fig. 37 (annotated).

The ’254 patent, Fig. 7 (labels repositioned; annotated).

The change from compression lug to nexus in the ’153 patent preserves the purported invention and benefits of the ’254 patent.  See, e.g., The ’153 patent at 6:16-25 (discussing the same purported advantages of the lead assembly as the ’254 patent).

Claim 1 of the ’153 patent recites:

A lead assembly for use in a solar energy installation including:

a drop line terminating at a drop line connector, the drop line connector configured to connect with a central trunk of a wire harness, the central trunk of the wire harness having a plurality of branches that each are configured to electrically connect to a separate solar panel contained in an array of a plurality solar panels;

a feeder cable electrically coupled to the drop line at a nexus;

an undermold that fully encases the nexus, the undermold further comprising:

a first aperture extending completely through the undermold and having a first diameter, wherein the feeder cable extends through the first aperture along a first longitudinal axis; and

a second aperture extending partially through the undermold and having a second diameter different than the first diameter, wherein the drop line extends from the second aperture along a second longitudinal axis;

a third aperture extending partially through the undermold and having a third diameter different than the first diameter, wherein a second drop line extends from the third aperture along a third longitudinal axis; and

an overmold surrounding the undermold and forming an undermold-overmold interface at an outer surface of the undermold.

The ’153 patent, 6:50-7:12.