PTAB challenges

Proceedings overview

Currently, there is one active Inter Partes Review (IPR) proceeding on U.S. Patent No. 11,374,508. This proceeding is in the initial "Pending Institution Decision" phase, meaning the patent claims have not yet been formally challenged in a trial and their validity remains untested by the PTAB. This gives a defendant limited defensive posture via PTAB proceedings at this stage, as no claims have been invalidated or sustained.

IPR2026-00333 — Toyota Motor Corporation et al. v. Bunker Hill Technologies, LLC

• Type: Inter Partes Review
• Filed: 2026-04-07
• Status: Pending Institution Decision. This means the Patent Trial and Appeal Board (PTAB) is currently reviewing the petition to determine whether to institute a trial.
• Judge panel: Not yet publicly assigned or determined at the institution decision stage.
• Petition grounds: Specific claims challenged, prior art, and statutory bases (§ 102 / § 103 / § 112) are typically detailed in the petition, which is not yet publicly available in detail for an IPR at this early stage of "Pending Institution Decision." However, the parallel district court litigation against Toyota (2:25-cv-01133) likely indicates that claims related to the dual-motor drive system, power split device, and energy management strategy are at issue.
• Institution decision: Not yet issued. The PTAB generally has a statutory deadline of six months from the date of the patent owner's preliminary response (or waiver thereof) to issue an institution decision. Given the filing date of 2026-04-07, this decision is anticipated in late 2026.
• Final Written Decision: Not issued, as the proceeding is pre-institution.
• Settlement / termination: Not applicable at this early stage.
• Appeal: Not applicable.
• Defensive value: As the IPR is still pending institution, it offers no immediate defensive value in terms of claims being canceled or sustained. However, the fact that an IPR has been filed indicates that a significant challenger (Toyota) believes there are strong validity arguments against the patent, likely based on prior art. Monitoring its progress is crucial.

Strategic summary

Currently, all claims of U.S. Patent No. 11,374,508 are UNTESTED by a PTAB Final Written Decision. IPR2026-00333 is in its nascent stage, with the PTAB yet to decide whether to institute a trial. Therefore, there are no canceled or sustained claims from PTAB proceedings at this time.

The estoppel landscape under § 315(e)(2) is not yet applicable, as no trial has been instituted, and no Final Written Decision has been issued. If IPR2026-00333 is instituted, the petitioner (Toyota Motor Corporation) and its privies would be barred from asserting in future civil actions or other USPTO proceedings any ground of invalidity that was raised or reasonably could have been raised during the IPR. Given the preliminary stage, all prior-art grounds remain theoretically available to other defendants.

There are no clear pattern signals of repeated IPR filings on this specific patent or aggressive PTAB appeals by the patent owner. The petitioner, Toyota Motor Corporation, is a significant entity, and their filing of this IPR suggests a strong challenge to the patent's validity in the context of their parallel district court litigation. Notably, the patent's assignee recently changed to Edison Innovations LLC, and the entity asserting the patent in litigation and defending in the IPR is Bunker Hill Technologies LLC, indicating potential litigation-focused ownership.

Recommended next steps

The IPR2026-00333 proceeding is currently "Pending Institution Decision."

• Monitor Institution Decision: The next critical milestone is the PTAB's decision on whether to institute the IPR. This decision will determine if a trial on the patentability of the challenged claims will proceed. The statutory deadline for this decision is typically six months from the preliminary response, expected in late 2026.
• Review Petition: Once the institution decision is made and the relevant documents are publicly accessible (if instituted), it will be crucial to review Toyota's petition in IPR2026-00333 to understand which specific claims were challenged and on what prior art and statutory grounds. This information will be invaluable for any entity facing assertion of this patent.
• Track Trial Milestones: If the IPR is instituted, track key trial stages, including the Patent Owner Response, Petitioner Reply, potential oral hearing, and the statutory one-year deadline for the Final Written Decision from the institution date.