DCT
1:20-cv-01622
REC Solar Pte Ltd v. Hanwha Solutions Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: REC Solar Pte. Ltd. (Singapore)
- Defendant: Hanwha Solutions Corporation (Republic of Korea) and Hanwha Q Cells USA, Inc. (Delaware)
- Plaintiff’s Counsel: Finnegan, Henderson, Farabow, Garrett & Dunner, LLP; Richards, Layton & Finger, P.A.
- Case Identification: 1:20-cv-01622, D. Del., 11/19/2021
- Venue Allegations: Venue is alleged to be proper in Delaware because Defendant Hanwha USA is a Delaware corporation, Defendant Hanwha Solutions has substantial contacts with the state, and infringing activities are alleged to have occurred in the district.
- Core Dispute: Plaintiff alleges that Defendant’s Q.Peak DUO and Q.Plus DUO solar modules infringe a patent related to a specific electrical configuration of solar cells and bypass diodes within a solar panel.
- Technical Context: The technology concerns the architecture of solar panel internal wiring, aiming to improve power output and reliability by mitigating the negative effects of partial shading on the panel.
- Key Procedural History: This First Amended Complaint was filed after the court granted a motion to dismiss a prior version without prejudice. The complaint also notes that the parties have a history of litigation, including a prior case before the ITC and in the District of Delaware on an unrelated patent, in which REC Solar received a final determination of non-infringement.
Case Timeline
| Date | Event |
|---|---|
| 2013-07-05 | U.S. Patent No. 10,749,060 Priority Date |
| 2018-03-01 | Hanwha allegedly introduced its Q.Peak DUO solar module |
| 2019-03-01 | Hanwha allegedly introduced its Q.Plus DUO solar module |
| 2020-08-18 | U.S. Patent No. 10749060 Issued |
| 2020-08-18 | Hanwha allegedly became aware of the ’060 Patent |
| 2020-11-23 | REC Solar allegedly provided Hanwha with notice of infringement |
| 2021-11-19 | First Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 10,749,060 - "SOLAR CELL ASSEMBLY" (issued August 18, 2020)
The Invention Explained
- Problem Addressed: The patent’s technical background describes how partial shading of a single solar cell in a conventional module can disproportionately reduce the power output of the entire module. This occurs because all cells are connected in series, and the shaded cell limits the current for the entire string. This condition can also lead to "hot-spots" where the shaded cell heats up, potentially damaging the module ('060 Patent, col. 1:26-50). While bypass diodes mitigate this, conventional layouts create a trade-off between cost and performance, a problem exacerbated when using more efficient "half-cut" cells ('060 Patent, col. 2:1-9, 2:15-24).
- The Patented Solution: The invention proposes a solar cell assembly divided into multiple "solar cell units" that are connected together in series. Critically, each individual unit contains two separate series of solar cells (e.g., two strings of half-cut cells) that are connected to each other in parallel. A single bypass diode is then coupled in parallel with this combined parallel arrangement ('060 Patent, Abstract; Fig. 2b). This architecture allows one series of cells within a unit to continue generating power even if the other series is shaded, improving overall module performance under non-ideal conditions ('060 Patent, col. 5:1-11). The patent also claims specific arrangements of junction boxes to house these bypass diodes.
- Technical Importance: This electrical architecture is presented as a way to increase module power output and robustness against partial shading without incurring the costs and manufacturing complexities of other solutions, such as those requiring excessive connector ribbons ('060 Patent, col. 2:31-35, col. 6:39-44).
Key Claims at a Glance
- Independent claim 1 is asserted in the complaint (Compl. ¶31).
- Essential elements of independent claim 1 include:
- A solar cell assembly comprising a first solar cell unit and a second solar cell unit coupled in series.
- The first solar cell unit comprises: (i) a first and second solar cell series, each with a plurality of half-cut cells, coupled in parallel with each other; (ii) a first bypass diode coupled in parallel with both the first and second series; and (iii) a first junction box containing the first bypass diode.
- The second solar cell unit mirrors the first, comprising: (i) a third and fourth solar cell series coupled in parallel; (ii) a second bypass diode coupled in parallel with the third and fourth series; and (iii) a second junction box containing the second bypass diode.
- The complaint asserts dependent claims 2-6, 11, and 13, and reserves the right to assert others (Compl. ¶43).
III. The Accused Instrumentality
Product Identification
- The complaint accuses Hanwha’s Q.Peak DUO and Q.Plus DUO solar module product lines of infringement (Compl. ¶2). The Q.Peak DUO-G5 325W product is used as a representative example for the infringement allegations (Compl. ¶35).
Functionality and Market Context
- The accused products are solar modules manufactured, sold, and imported in the United States (Compl. ¶32). The complaint alleges these products implement the patented technology by employing a specific architecture of series-connected solar cell units, where each unit contains parallel-connected strings of half-cut cells protected by a bypass diode housed in a junction box (Compl. ¶¶35-42). The complaint provides an annotated photograph showing the accused product is comprised of a "first solar cell unit (blue) coupled in series with a second solar cell unit (purple)" (Compl. ¶35). The complaint alleges that Hanwha adopted REC Solar's technology for its own products (Compl. ¶26).
IV. Analysis of Infringement Allegations
'060 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a first solar cell unit, comprising: a first solar cell series including a plurality of half-cut solar cells connected in series | The accused Q.Peak Sample product has a first solar cell unit that contains a first solar cell series. An annotated image shows these half-cut cells are connected in series. | ¶36, ¶37 | col. 4:32-41 |
| a second solar cell series, coupled in parallel with the first solar cell series, including a plurality of half-cut solar cells… | The first solar cell unit also contains a second solar cell series, which is coupled in parallel with the first series. An annotated image in the complaint illustrates this parallel coupling. | ¶36, ¶38 | col. 4:3-13 |
| a first bypass diode coupled in parallel with the first solar cell series and the second solar cell series | The Q.Peak Sample is alleged to include a first bypass diode, located on the back of the assembly, that is coupled in parallel with both the first and second solar cell series. | ¶39 | col. 4:55-61 |
| a first junction box containing the first bypass diode | The first bypass diode is allegedly contained within a first junction box. The complaint includes a photograph of the back of the panel with a structure identified as the junction box highlighted. | ¶40 | col. 5:26-34 |
| a second solar cell unit, coupled in series with the first solar cell unit | The accused product allegedly has a second solar cell unit that is coupled in series with the first solar cell unit. | ¶35 | col. 3:28-33 |
| [comprising a third solar cell series... a fourth solar cell series... a second bypass diode...] | The complaint alleges the second solar cell unit mirrors the first, containing a third and fourth solar cell series coupled in parallel, which are in turn coupled in parallel with a second bypass diode. | ¶41, ¶42 | col. 4:3-13 |
| a second junction box containing the second bypass diode | The second bypass diode is allegedly contained within a second junction box on the back of the accused product. | ¶42 | col. 5:34-37 |
- Identified Points of Contention:
- Technical Questions: The complaint’s infringement theory relies on a direct structural and electrical mapping. A key factual question for discovery will be whether the internal circuitry of the accused products functions precisely as alleged. For example, what evidence confirms that the electrical connection between the cell series within a unit is "in parallel" as understood in the patent, and that the bypass diodes operate across both parallel series as claimed? The complaint's visual evidence, showing what it identifies as half-cut cells connected in series, provides a basis for this allegation (Compl. ¶37).
- Scope Questions: Claim 1 recites "a first junction box" and "a second junction box." A potential point of contention is whether the physical housing(s) on the back of the accused panel meet this limitation. A defendant could argue that the product uses a single, internally partitioned housing for the diodes, which would raise the question of whether such a structure constitutes two distinct "junction boxes" as required by the claim's plain language. The complaint provides a diagram from a product datasheet showing multiple distinct boxes on the back of the panel (Compl. ¶39).
V. Key Claim Terms for Construction
- The Term: "a first junction box ... and a second junction box"
- Context and Importance: The infringement analysis for claim 1 hinges on whether the accused products possess two distinct structures that meet the definition of a "junction box." If the accused products are found to use a single physical housing that contains multiple bypass diodes, even in separate compartments, Hanwha may argue it does not literally infringe this element. Practitioners may focus on this term because it involves a specific physical structure that is readily observable and less ambiguous than functional limitations.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party seeking a broader definition might argue that the term "junction box" should functionally refer to any enclosure for the bypass diode and its connections. The patent specification refers to a junction box as a "fixture for the cables used to connect the module to neighboring modules" ('060 Patent, col. 1:43-45) and later discusses using "a plurality of junction boxes" ('060 Patent, col. 5:34-35), which could be interpreted to mean functionally separate connection points, regardless of their integration into a single molded piece of plastic.
- Evidence for a Narrower Interpretation: A party seeking a narrower definition would emphasize the plain language of the claim, which recites two separate components: "a first junction box" and "a second junction box." They could argue this requires two physically separate and distinct housings. This argument may find support in the specification’s separate discussion of an embodiment with "a single junction box housing all by-pass diodes" ('060 Patent, col. 5:52-55), suggesting the patentee knew how to claim a single box but chose not to in claim 1.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement, stating that Hanwha sells the accused products with the knowledge and intent that its customers, including distributors, installers, and end-users, will directly infringe by using the products as intended (Compl. ¶44). The allegations are supported by reference to Hanwha's marketing and sales teams and sales to installers in Delaware (Compl. ¶44).
- Willful Infringement: Willfulness is alleged based on both pre-suit and post-suit knowledge of the ’060 Patent (Compl. ¶45). The complaint alleges Hanwha was aware of the patent as of its issue date on August 18, 2020, and received specific notice of infringement from REC Solar on November 23, 2020 (Compl. ¶25). Continued infringing conduct after receiving such notice is alleged to be willful and deliberate (Compl. ¶45).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural correspondence: Does the physical and electrical architecture of Hanwha's accused solar modules, as established through technical evidence, align with the specific multi-unit, parallel-series, and dual-junction-box structure recited in claim 1? The complaint’s use of annotated product photographs suggests a direct mapping, but the ultimate determination will rest on detailed evidence of the products' construction and operation.
- The case may also turn on a question of claim scope: Can the claim term "a second junction box" be construed to read on a product that potentially uses a single, consolidated housing with multiple, internally-partitioned compartments for different bypass diodes, or does the claim require two physically separate and distinct enclosures? The resolution of this question could be dispositive for the literal infringement analysis.