DCT

2:25-cv-00048

LONGi Green Energy Technology Co Ltd v. JinkoSolar Holding Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00048, E.D. Tex., 01/17/2025
  • Venue Allegations: Venue is alleged to be proper as Defendants are foreign corporations and have conducted substantial business in the district, including supplying large-scale solar projects, maintaining warehouse facilities in Houston, and selling products through a network of local distributors.
  • Core Dispute: Plaintiff alleges that Defendant’s solar modules, which utilize a divided-cell architecture, infringe a patent related to a specific method of arranging and interconnecting those cells to increase power output.
  • Technical Context: The technology addresses a key challenge in solar panel design: reducing electrical resistance losses that become more significant as cell efficiency increases, thereby improving overall module performance.
  • Key Procedural History: The patent-in-suit was assigned from its original owner, Mitsubishi Electric Corporation, to Plaintiff LONGi Green in 2020. The complaint alleges that Defendant had pre-suit knowledge of the patent family via citations in its own patent applications dating back to 2015, and also received direct notification of infringement in August 2024.

Case Timeline

Date Event
2010-07-02 '214 Patent Priority Date (PCT Filing)
2015-06-17 Publication of Jinko patent application allegedly citing '214 patent family
2016-12-06 '214 Patent Issue Date
2020-07-03 Publication of Jinko patent application allegedly citing '214 patent family
2020-10-20 '214 Patent assigned to LONGi Green
2024-08-01 Alleged notification of infringement from LONGi to Jinko (approx. date)
2025-01-17 Complaint Filing Date

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

U.S. Patent No. 9,515,214 - "Solar Battery Module and Manufacturing Method Thereof,"

  • Issued: December 6, 2016

The Invention Explained

  • Problem Addressed: As solar cells become more efficient, they generate higher electrical currents. This increased current leads to greater power loss due to electrical resistance in the metal interconnectors that wire the cells together, limiting the overall module's performance improvement (’214 Patent, col. 1:12-27).
  • The Patented Solution: The patent describes a solar module architecture that mitigates this resistance loss. The core concept is to divide a conventional square solar cell into "n" smaller, substantially rectangular cells (e.g., "half-cells," where "n=2") (’214 Patent, col. 2:39-42). This division effectively halves the current carried by each cell's interconnectors. These smaller cells are then arranged in a specific electrical configuration: "n" columns of serially-connected cell strings are connected to each other in parallel, and these parallel groups are then connected in series with other, similar parallel groups to form the complete module (’214 Patent, col. 11:58-col. 12:17; Fig. 12).
  • Technical Importance: This design allows module manufacturers to increase power output by reducing internal resistive losses without requiring wider interconnectors that would block light or thicker interconnectors that could increase mechanical stress on the cells (’214 Patent, col. 1:42-53).

Key Claims at a Glance

  • The complaint asserts independent claim 1 of the ’214 Patent (Compl. ¶ 50).
  • The essential elements of independent claim 1 include:
    • A plurality of solar battery cells, each being a "substantial rectangle" with a side length ratio of 1/n:1, where n ≥ 2.
    • An interconnector to electrically connect the light-receiving-surface (front) bus electrodes of one cell to the rear-surface bus electrodes of an adjacent cell, forming a "cell string."
    • An architecture where "n columns of the cell strings are connected in parallel by a first string connector."
    • A specific constraint that the number of parallel columns ("n") must be "equal to the n in the ratio of the long side length to the short side length" of the cell itself.
    • The "n-column parallel-connected cell strings are further serially connected to another n-column parallel-connected cell strings by a second string connector... thereby configuring an entire cell array."

III. The Accused Instrumentality

Product Identification

  • A wide range of Jinko solar modules are accused, including numerous models from the "EAGLE," "Cheetah," and "Tiger Neo" product families (Compl. ¶ 53).

Functionality and Market Context

  • The accused products are solar modules sold for residential, commercial, and utility-scale projects (Compl. ¶¶ 3, 29, 30). The complaint alleges these modules employ a divided-cell (e.g., half-cut cell) design to achieve high power output (Compl. ¶¶ 42-43). The complaint presents visual evidence to support its allegations regarding the products' origins and distribution. A product label for the Jinko JKM425N-54HL4-B module specifies its technical characteristics and identifies its origin as "Made in Vietnam" with Jinko China as the supplier (Compl. p. 4). Another product label for the Jinko JKM390M-72HBL-V module states it was "Modules assembled in the USA from solar cells made in Vietnam," which supports the contributory infringement allegations (Compl. p. 6). The complaint alleges Jinko is one of the world's largest solar module manufacturers and has an extensive sales and distribution network throughout the United States, including Texas (Compl. ¶¶ 5, 31, 33). A map from Jinko's website illustrates its U.S. distributor network, including multiple locations in Texas, which is used to support venue allegations (Compl. p. 15).

IV. Analysis of Infringement Allegations

The complaint references a claim chart in an exhibit that was not provided with the filing (Compl. ¶ 52). The narrative infringement theory presented in the complaint is that Jinko’s accused solar modules, which are widely marketed as using half-cell technology, practice the specific architecture claimed in the ’214 Patent (Compl. ¶¶ 42-43, 50). The core of the allegation is that Jinko’s modules are constructed from solar cells divided in half (making "n=2"), which are then wired into an array where two columns of cell strings are connected in parallel, and these parallel-connected groups are subsequently connected in series, thereby mapping directly onto the limitations of claim 1.

  • Identified Points of Contention:
    • Scope Questions: Claim 1 requires that the number of parallel-connected columns ("n") be "equal to the 'n' in the ratio of the [cell's] long side length to the short side length." This creates a rigid link between the cell's physical geometry and its electrical layout. A central question will be whether the internal wiring of the accused modules strictly adheres to this "n=n" constraint.
    • Technical Questions: The complaint's allegations are based on the general and advertised features of the accused products. A key issue for discovery will be to obtain detailed technical specifications and electrical schematics of the accused modules. What evidence will show that the modules contain a "first string connector" and a "second string connector" that perform the distinct parallel and serial connection steps as claimed, rather than a more integrated or functionally different connection scheme?

V. Key Claim Terms for Construction

  • The Term: "substantial rectangle"

    • Context and Importance: This term defines the shape of the fundamental component, the solar cell. Its construction is important because many modern high-efficiency cells feature cut or chamfered corners, and the patent itself discloses a "corner-cut solar battery cell" as an embodiment (’214 Patent, col. 9:51-57; Fig. 13). Practitioners may focus on this term to determine if such common commercial designs fall within the claim's scope.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The use of the word "substantial" implies that minor deviations from a perfect geometric rectangle are contemplated. The specification's explicit inclusion of an embodiment with cut corners could be cited to argue that such shapes are encompassed by the term (’214 Patent, Fig. 13).
      • Evidence for a Narrower Interpretation: The primary embodiment and description focus on cells formed by cleanly dividing a square wafer, resulting in a classic rectangle (’214 Patent, col. 4:31-44). An argument could be made that "substantial" only permits de minimis imperfections, and that significantly altered shapes like those with large corner cuts are distinct from the claimed "substantial rectangle."

  • The Term: "n columns of the cell strings are connected in parallel"

    • Context and Importance: This phrase, particularly when combined with the "n=n" constraint discussed in Section IV, is the defining architectural limitation of the claim. The infringement analysis will turn on whether the accused modules' electrical layouts literally meet this specific structural requirement.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent's objective is to reduce resistance loss by dividing current (’214 Patent, col. 2:35-39). A party might argue that alternative wiring schemes that achieve this same parallel connection function should be considered equivalent.
      • Evidence for a Narrower Interpretation: The claim language is highly specific, requiring a connection of "'n' columns" in "parallel." Figure 12 clearly depicts two distinct columns (17A, 17B) being joined by a string connector (16) to form a parallel-connected group (18A) (’214 Patent, Fig. 12). A party could argue that this requires a literal parallel circuit of exactly "n" columns, and any other configuration (e.g., a mesh or a series-parallel hybrid within the group) would not infringe.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement by asserting that Defendants knowingly encourage infringement by their distributors and customers through the sale of the accused modules and by providing installation instructions (Compl. ¶¶ 54, 57). It also alleges contributory infringement by claiming Defendants import "specially made solar cells" that are a material part of the invention and not a staple article of commerce, for the express purpose of assembly into the infringing modules in the U.S. (Compl. ¶ 58).
  • Willful Infringement: Willfulness is alleged based on both pre- and post-notification conduct. The complaint alleges Defendants had knowledge of the patent family as early as 2015 from citations in their own pending patent applications (Compl. ¶ 55). It further alleges that Plaintiff provided direct notice of infringement to an agent of the Defendants in August 2024, and that Defendants' continued infringing activities thereafter have been willful (Compl. ¶¶ 56, 60).

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

  • A core issue will be one of structural and definitional precision: Can the specific architectural limitation of claim 1—requiring "'n' columns of cell strings...connected in parallel" where the number of columns "n" is strictly equal to the cell's aspect ratio "n"—be proven to read literally on the internal wiring of the accused Jinko modules?
  • A key evidentiary question will be one of proving technical implementation: Beyond marketing materials, what will discovery and reverse engineering reveal about the actual electrical schematics of the numerous accused product lines, and will that evidence demonstrate a clear and consistent application of the patented architecture?
  • A third pivotal question relates to culpability and damages: Does the allegation that Defendants’ own patent applications cited the asserted patent family as prior art constitute sufficient pre-suit knowledge to support a finding of willful infringement, potentially leading to enhanced damages if infringement is found?