US ITC Issues Partial Final Determination in 337 Investigation on TOPCon Solar Cells

On May 27, 2026, the U.S. International Trade Commission (ITC) issued a partial final determination in its Section 337 investigation concerning TOPCon solar cells and modules, approving BYD America Co., Ltd. as a third-party intervenor. This development directly affects manufacturers and exporters of photovoltaic equipment, industrial power supplies, and inverters — particularly those supplying to the U.S. market — and warrants close attention from companies engaged in cross-border trade, component integration, and supply chain compliance.

Event Overview

On May 27, 2026, the U.S. International Trade Commission (ITC) issued a partial final determination in Investigation No. 337-TA-1412 concerning TOPCon solar cells and modules. The complaint was filed by First Solar, alleging infringement of U.S. Patent No. US9130074. The ITC approved BYD America Co., Ltd. as a third-party intervenor. The investigation remains ongoing; no final determination on violation or remedy has been issued at this stage.

Industries Affected by Segment

Direct Exporters of Photovoltaic Modules and Cells

Companies exporting TOPCon solar cells or modules to the U.S. face heightened risk of customs detention or exclusion if a general exclusion order is ultimately issued. The ITC’s partial final determination signals advancing procedural momentum toward potential remedial action, affecting shipment planning, documentation requirements, and tariff classification verification for U.S.-bound consignments.

Manufacturers of Integrated Energy Systems (e.g., PV + Storage)

Because the investigated products are widely used in utility-scale solar farms and energy storage system integration, firms assembling or branding integrated solutions containing TOPCon cells may encounter downstream compliance scrutiny. U.S. importers and system integrators may request updated technical documentation or patent indemnity clauses, increasing contractual and operational due diligence burdens.

Suppliers of Associated Power Electronics

The notice explicitly identifies industrial power supplies and inverters as part of the affected ecosystem. While not directly accused of infringement, suppliers whose products are marketed or deployed alongside the investigated TOPCon modules may face indirect commercial pressure — including requests for alternative sourcing, revised compatibility certifications, or enhanced supply chain transparency disclosures — especially from U.S. distributors prioritizing regulatory continuity.

Key Points for Enterprises and Practitioners to Monitor and Act Upon

Track Official ITC Filings and Public Record Updates

Monitor the ITC’s official docket (Investigation No. 337-TA-1412) for subsequent filings, including the presiding administrative law judge’s initial determination (if issued), Commission review decisions, and any public versions of remedy recommendations. These documents will clarify whether a limited or general exclusion order is proposed — a distinction with material implications for scope and enforceability.

Review Product-Specific Technical Documentation Against Claimed Patent Claims

For affected exporters and their U.S. importers, align internal technical specifications (e.g., cell architecture, passivation layer composition, metallization design) with the asserted claims of US9130074. This supports informed risk assessment and enables timely engagement with legal counsel regarding non-infringement positions or design-around feasibility — particularly where product variants exist across model lines or generations.

Evaluate Customs Entry Protocols and Partner Communication Plans

Assess current U.S. customs entry procedures for affected goods, including Harmonized Tariff Schedule (HTS) classifications and prior disclosure practices. Proactively coordinate with U.S. customs brokers and importers to confirm alignment on documentation expectations, and consider developing contingency messaging for customers regarding possible delays or reclassification requirements pending final ITC action.

Editorial Perspective / Industry Observation

Observably, this partial final determination does not yet constitute a binding remedial order — it reflects procedural progress rather than a concluded finding of violation. Analysis shows that the ITC’s approval of BYD America as a third-party intervenor expands the range of stakeholders formally participating in the record, potentially influencing evidentiary scope and remedy considerations. From an industry perspective, the case functions more as a signal of intensified IP enforcement focus on advanced cell technologies than as an immediate operational constraint. However, because TOPCon represents a growing share of high-efficiency module exports, sustained attention is warranted as the investigation moves toward final Commission action.

Concluding, this ITC development underscores how patent-based trade remedies increasingly intersect with technical differentiation in next-generation photovoltaics. It is not yet a market access barrier, but rather a compliance inflection point requiring structured monitoring and cross-functional coordination across legal, supply chain, and export operations teams. Current understanding should treat it as a procedural milestone with forward-looking implications — not a finalized restriction.

Source: U.S. International Trade Commission (ITC) official docket for Investigation No. 337-TA-1412; public notice dated May 27, 2026. Ongoing developments — including the Commission’s final determination and any recommended relief — remain subject to further official updates and require continued observation.