The Shifting Sands of Divisional Patents: What NOCO v Brown & Watson Means for the 'Best Method' Requirement

When the Full Court of the Federal Court of Australia handed down its decision in The NOCO Company v Brown & Watson International Pty Ltd, it didn't just resolve a commercial dispute over portable jump starters. It fundamentally altered the strategic landscape for filing divisional patent applications in Australia.

For patent applicants and IP practitioners, this appellate decision serves as a stark warning: treating a divisional application as a simple "copy-paste" of its parent specification now carries the ultimate risk of patent invalidation.

Here is our breakdown of the Full Court's reasoning and what it means for your ongoing patent strategies.

The Core Dispute: Jump Starters and Safety Tech

The litigation centred on three divisional patents owned by US-based The NOCO Company, covering portable, lithium-ion vehicle jump starters equipped with specific safety features. NOCO alleged that Brown & Watson International (B&W) infringed these patents through its "Projecta" product line.

B&W fiercely defended the claim, launching a cross-claim that attacked the validity of NOCO's patents on multiple fronts. The primary judge ruled in favour of B&W across the board, and NOCO appealed. The Full Court's unanimous dismissal of that appeal cemented several critical interpretations of Australian patent law.

The Bombshell: Timing the "Best Method" Requirement

The most consequential aspect of the judgment deals with Section 40(2)(aa) of the Patents Act 1990, which requires a patent specification to disclose the best method known to the applicant for performing the invention.

The legal friction point was temporal: for a divisional application, do we assess the applicant's knowledge at the filing date of the original parent application, or at the actual filing date of the divisional?

The Full Court firmly established that the relevant date is the filing date of the divisional application.

This proved fatal for NOCO. After filing their initial parent application in 2014, NOCO made commercial improvements to their jump starters — specifically incorporating a larger lithium-ion battery and changing a switch mechanism to resolve operational issues. However, when they filed their divisional applications between 2020 and 2022, they did not update the specifications to reflect these improved methods. Because NOCO possessed a "better method" at the time the divisionals were actually filed but kept it out of the specification, the Court ruled the patents invalid.

Claim Construction and the "Only When" Trap

Even putting validity aside, NOCO failed on infringement due to strict claim construction.

NOCO's patent claims were drafted with limiting conditional language, asserting that the jump starter would supply power "only when" specific safety preconditions were satisfied (such as detecting that the battery was correctly connected).

B&W's Projecta devices, however, featured a manual override function. This allowed a user to force the device to deliver power even if the safety conditions were not met. The Full Court agreed with the primary judge's literal interpretation: because the B&W device could supply power outside of those strict preconditions, it circumvented the "only when" limitation entirely.

Lost Priority and the Trap of Obviousness

NOCO's patents also collapsed under standard validity attacks. To survive, NOCO needed to rely on the 2014 priority date of the parent application. However, the Full Court affirmed that the parent specification did not clearly and unambiguously disclose the exact invention claimed in the later divisionals.

Severed from the 2014 priority date, the divisional claims were evaluated against the common general knowledge available in 2020–2022. The Court concluded that taking a standard jump starter and adding off-the-shelf technologies — like a lithium-ion power pack and a USB port — did not require an inventive step. It was merely a routine workshop variation for a skilled tradesperson, rendering the claims obvious.

Strategic Takeaways for Innovators

The NOCO decision requires an immediate shift in how companies manage their Australian patent portfolios.

• Divisional Filings Require Review: You can no longer assume that a divisional application should perfectly mirror its parent. If your R&D team has developed better ways to perform the invention since the parent was filed, you must seriously consider whether those improvements need to be drafted into the divisional specification to satisfy the best method requirement.

• The Trade Secret Dilemma: This creates a strategic tension. Companies often prefer to keep post-filing manufacturing improvements as trade secrets. Under this new precedent, withholding those improvements when filing an Australian divisional could poison the resulting patent.

• Drafting Precision: The failure of NOCO's infringement claim highlights the danger of overly absolute language like "only when." Claims must be drafted with enough flexibility to capture competitors who design around specific conditional limitations.

If you have pending divisional applications or are considering your filing strategy for an evolving product line, contact Stellar IP Law today to ensure your portfolio remains robust and enforceable.