DCT

3:24-cv-08828

Shanghai Jinko Green Energy Enterprises Management Co Ltd v. Abalance Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:24-cv-08828, N.D. Cal., 12/06/2024
  • Venue Allegations: Venue is alleged to be proper in the Northern District of California because Defendant VSUN Solar USA Inc has a regular and established place of business in the district and has committed acts of infringement there.
  • Core Dispute: Plaintiff alleges that Defendant’s TOPCON N-type solar panels infringe two patents related to the specific micro-scale surface structures of solar cells designed to enhance efficiency.
  • Technical Context: The dispute is centered on high-efficiency N-type TOPCon (Tunnel Oxide Passivated Contact) photovoltaic technology, a key area of competition and innovation in the global solar panel market.
  • Key Procedural History: The complaint does not reference any prior litigation, inter partes review (IPR) proceedings, or licensing history between the parties concerning the asserted patents.

Case Timeline

Date Event
2021-08-04 Priority Date for '454 and '136 Patents
2023-02-14 '454 Patent Issue Date
2023-11-21 '136 Patent Issue Date
2024-12-06 Complaint Filing Date

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

U.S. Patent No. 11,581,454 - "Solar Cell, Manufacturing Method Thereof, and Photovoltaic Module"

  • Patent Identification: U.S. Patent No. 11,581,454, issued February 14, 2023.
  • The Invention Explained:
    • Problem Addressed: In the manufacturing of N-type TOPCon solar cells, the process of removing borosilicate glass from the rear of the silicon wafer often results in a polished, flat rear surface. The patent asserts that this flat structure can negatively affect the performance of subsequent critical layers (the tunnel oxide and polycrystalline silicon layers), thereby limiting the cell's overall passivation and conversion efficiency ('454 Patent, col. 1:20-40).
    • The Patented Solution: The invention proposes creating a specific, non-uniform surface topography. It combines a conventional pyramid-shaped texture on the front (light-receiving) surface with a novel "non-pyramid microstructure" on the rear surface ('454 Patent, col. 1:41-48, col. 2:2-13). This rear-surface texture is described as being composed of two or more "first substructures at least partially stacked on one another," creating what the specification refers to as a "substantially 'step' profile" ('454 Patent, col. 8:49-51).
    • Technical Importance: This dual-textured approach is intended to create a "light trap structure at different levels," which increases the effective area for light absorption while also improving the uniformity and performance of the passivated contact layers on the rear surface, ultimately boosting the cell's conversion efficiency ('454 Patent, col. 10:22-38).
  • Key Claims at a Glance:
    • The complaint asserts at least independent claim 1 (Compl. ¶35).
    • The essential elements of independent claim 1 include:
      • A semiconductor substrate with a rear surface having a "first texture structure."
      • This first texture structure has a "non-pyramid microstructure" that includes "two or more first substructures at least partially stacked on one another," with the top surface of the substructure being a "polygonal plane."
      • The claim recites specific dimensional constraints, including the distance between adjacent stacked substructures (≤ 2µm) and the average size of the outermost substructure (10 µm to 15 µm).
      • The claim also requires a first passivation layer on the front surface, a tunnel oxide layer on the rear textured surface, a doped conductive layer, and a second passivation layer.

U.S. Patent No. 11,824,136 - "Solar Cell, Manufacturing Method Thereof, and Photovoltaic Module"

  • Patent Identification: U.S. Patent No. 11,824,136, issued November 21, 2023.
  • The Invention Explained:
    • Problem Addressed: The '136 Patent, a divisional of the application leading to the '454 Patent, addresses the same technical problem: overcoming the performance limitations associated with a flat, polished rear surface in TOPCon solar cells ('136 Patent, col. 1:20-40).
    • The Patented Solution: The solution is substantively identical to that of the '454 Patent, describing a solar cell that matches a specific "non-pyramid microstructure" on the rear surface with a "pyramid-shaped microstructure" on the front surface. The core inventive concept of a dual-sided, engineered texture to improve efficiency is maintained ('136 Patent, Abstract; col. 2:2-13).
    • Technical Importance: The patent asserts that this specific combination of front and rear surface textures improves light trapping and enhances the performance of the passivated contact structure, leading to higher overall cell efficiency ('136 Patent, col. 10:22-38).
  • Key Claims at a Glance:
    • The complaint asserts at least independent claim 1 (Compl. ¶43).
    • The essential elements of independent claim 1 are similar to claim 1 of the '454 Patent but explicitly combine the front and rear features into the base claim:
      • A semiconductor substrate with a rear surface having a "first texture structure" that is a "non-pyramid-shaped microstructure" with "partially stacked" substructures.
      • The claim also requires that the front surface has a "second texture structure" which includes a "pyramid-shaped microstructure."
      • The claim then recites the standard stack of layers: a first passivation layer on the front surface, a tunnel oxide layer on the rear surface, a doped conductive layer, and a second passivation layer.

III. The Accused Instrumentality

Product Identification

The complaint identifies "VSUN's TOPCON N-type solar module series" as the Accused Solar Panels (Compl. ¶27). It provides a non-exhaustive list of dozens of specific model numbers, such as VSUN575N-144BMH-DG and VSUN715N-132BMHT-DG (Compl. ¶27).

Functionality and Market Context

The complaint alleges that the Accused Solar Panels are high-efficiency photovoltaic modules that directly compete with Jinko's products for the same customers and applications (Compl. ¶16). It is alleged that these products are made, used, sold, offered for sale, and/or imported in the United States (Compl. ¶27). The complaint references a webpage showing an accused VSUN570N-144BMH-DG model installed at the Cincinnati Zoo & Botanical Garden in Ohio (Compl. ¶29, n.4).

IV. Analysis of Infringement Allegations

The complaint references claim chart exhibits (Exhibits 3 and 4) that were not publicly filed with the initial pleading. The infringement analysis is therefore based on the narrative allegations in the complaint.

  • '454 Patent Infringement Allegations: The complaint alleges that the Accused Solar Panels directly infringe, literally or under the doctrine of equivalents, one or more claims of the '454 Patent (Compl. ¶34). It asserts that these products meet "each and every one of the claim limitations of at least claim 1," and refers to an unprovided Exhibit 3 for detailed mapping (Compl. ¶35). The core of the infringement theory is that VSUN's TOPCON N-type panels possess the patented multi-layered structure, including the specific "non-pyramid microstructure" with stacked substructures on the rear surface of the solar cell.

  • '136 Patent Infringement Allegations: Similarly, the complaint alleges that the Accused Solar Panels infringe one or more claims of the '136 Patent (Compl. ¶42). The pleading states that the products meet all limitations of at least claim 1 and references an unprovided Exhibit 4 (Compl. ¶43). The infringement theory for the '136 Patent relies on the allegation that VSUN's products contain the combination of the claimed non-pyramidal rear-surface texture and the pyramid-shaped front-surface texture.

  • Identified Points of Contention:

    • Evidentiary Questions: The complaint's allegations are made "on information and belief" and lack specific, publicly available technical evidence (e.g., scanning electron microscopy images) to substantiate the claim that the Accused Solar Panels contain the patented microstructures. A central question for discovery will be: What evidence can Jinko produce to demonstrate that the rear surfaces of VSUN's commercially manufactured solar cells actually possess the specific "non-pyramid microstructure" with "partially stacked" substructures that meet the dimensional limitations of the asserted claims?
    • Technical Questions: The patents claim a highly specific, engineered surface geometry. The infringement analysis may turn on whether VSUN's manufacturing process creates this exact structure or a different, non-infringing texture that achieves a similar functional result.

V. Key Claim Terms for Construction

  • The Term: "non-pyramid microstructure"

    • Context and Importance: This term is central to distinguishing the invention from the prior art and defines the core feature of the rear surface. Its construction will determine whether the claims cover a wide array of textured surfaces or are limited to the specific "step-like" structures shown in the patent.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The term is defined negatively ("non-pyramid"), which could support an interpretation covering any rear surface texture that is not the conventional pyramidal shape used on front surfaces.
      • Evidence for a Narrower Interpretation: The specification repeatedly describes the structure as creating a "substantially 'step' profile" and includes figures (e.g., Fig. 3, 4a) depicting distinct, layered, polygonal substructures ('454 Patent, col. 8:49-51). A party could argue the term is limited by these specific embodiments.

  • The Term: "two or more first substructures at least partially stacked on one another"

    • Context and Importance: This phrase gives three-dimensional character to the "non-pyramid microstructure" and is critical for proving infringement. The dispute will likely focus on what degree of vertical overlap and geometric regularity is required to meet this limitation.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: A party might argue that "partially stacked" merely requires some vertical overlap between adjacent surface features, without regard to shape or regularity.
      • Evidence for a Narrower Interpretation: The patent figures (Fig. 4a, 4b) illustrate a clear, ordered stacking of planar structures ('454 Patent, Sheet 2). Furthermore, the claims recite specific distance limitations between these "adjacent" substructures, suggesting a more structured and less random arrangement is contemplated ('454 Patent, Claim 1).

VI. Other Allegations

  • Indirect Infringement: The complaint makes boilerplate allegations of induced and contributory infringement. It alleges inducement based on the assertion that VSUN "understand[s], intend[s], and encourage[s]" the importation and use of the accused products in the U.S. (Compl. ¶37, ¶45). It alleges contributory infringement on the basis that the accused panels are a material part of the invention, are not staple articles of commerce, and are especially made for infringement (Compl. ¶38, ¶46).

  • Willful Infringement: Willfulness is alleged based on both pre- and post-suit knowledge. The complaint alleges that as an "active competitor," VSUN would have investigated Jinko's patent portfolio and thus had knowledge of the patents since their issuance (Compl. ¶31). It also asserts knowledge at least as of the date the complaint was filed, supporting a claim for ongoing willful infringement (Compl. ¶32).

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

The resolution of this case appears to hinge on two primary questions, one evidentiary and one legal.

  • A central issue will be evidentiary proof: As the complaint was filed without public-facing technical analysis of the accused products, the case will depend on whether Jinko can develop factual evidence through discovery to show that VSUN's mass-produced solar cells actually contain the specific, dimensionally-constrained "non-pyramid microstructure" on their rear surface as required by the asserted claims.

  • A key legal battle will be over claim scope: The court's construction of terms like "non-pyramid microstructure" and "partially stacked on one another" will be dispositive. The question is whether these terms will be interpreted narrowly to cover only the specific "step-like" polygonal structures depicted in the patents' embodiments, or more broadly to encompass a wider range of non-uniform rear surface textures, fundamentally altering the challenge of proving infringement.