Although solid state electrolytes are all the rage right now, let’s not forget that liquid electrolytes are still very much holding their own. Ube Industries, Ltd. of Japan and its subsidiary Advanced Electrolyte Technologies LLC (collectively Ube) continue the successful enforcement and licensing of their lithium-ion electrolyte patent portfolio.

Ube has now filed and settled three patent infringement suits against Samsung SDI, Zhuhai Coslight Battery, and BYD Lithium Battery. Ube first filed suit against Samsung SDI and related entities in January 2017 in the U.S. District Court for the Western District of Texas. Ube then filed suit against Coslight in October 2018. Finally, Ube filed suit against BYD in June 2020. Of the three manufacturers, Samsung litigated the asserted patents the most extensively, settling well after claim construction and institution decisions in inter partes reviews (IPRs) of the asserted patents. Coslight and BYD settled their suits before any significant proceedings.

In the suits, Ube accused any lithium-ion cells utilizing a non-aqueous electrolyte to be infringing. This effectively accused the cell manufacturers' entire lithium-ion cell lineups given the the predominance of non-aqueous electrolytes in current lithium-ion cells.

From its electrolyte portfolio, Ube asserted U.S. Patent Nos. 6,033,809, 6,927,001, 9,742,033, and 10,050,307, which together appear to provide broad and varied coverage over the accused infringing electrolyte solutions. The patents are all generally directed to electrolyte solutions with a sultone additive. The '809 and '001 patents are directed to an electrolyte solution comprising a cyclic carbonate, a linear carbonate, and a sultone derivative. The '809 patent, with the earliest priority date amongst the asserted patents, further claims that the cyclic carbonate is to be present 10 to 70% by weight, the linear carbonate 30 to 90% by weight, and the sultone additive present by 0.1 to 4% by weight. The '033 patent and '307 patents claim a electrolyte solution comprising a cyclic carbonate, a sultone compound, and a LiPF6 (lithium hexafluorophosphate) or LiBF4 (lithium tetrafluoroborate) electrolyte.

The asserted Ube patents appear to be challenging to invalidate. The '809 and '001 patents claim priority to Japanese patent applications with priority dates in 1997 and 1999 respectively. The '033 and '307 patents claim priority back to 2002. The PTAB declined to institute the IPRs on the '809 and '001 patents and only instituted on the '033 patent. In the IPR of the '809 patent, the PTAB denied institution because the nearest prior art failed to disclose the inclusion of a cyclic and a linear carbonate with the sulton additive in the claimed amounts. The PTAB found that the nearest prior art at most disclosed a 50:50 mixing of a cyclic carbonate and a linear carbonate, or a 50:50 mixture of a sultone compound and a linear carbonate, but did not teach or suggest a significant amount of cyclic carbonate and a linear carbonate together with a small amount of sultone additive.

Ube’s licensing campaign likely began as early as 2015. Although the suit was first filed in 2017, Ube's complaint against BYD states that Ube provided a detailed list of Ube electrolyte patents to BYD as early as February 2015 and that it attempted to engage in licensing negotiations from 2019 to 2020 before filing suit.

Ube's enforcement of its lithium-ion electrolyte patents is likely only the tip of the iceberg in the coming tide of patent litigation in battery technology. With the meteoric growth of electric vehicles and energy storage, many new market participants, manufacturing and not-manufacturing, have entered the space. Battery R&D and patent activity have also skyrocketed. The European Patent Office reported a 14% growth of patent families related to electricity storage between 2005 and 2018 (of which 88% are directed to battery technology), compared to just 3.5% for all technology areas. The EPO also reported an increase in patenting activity of solid-state battery technologies by an average of 25% per year since 2010. Inevitably, this increased competition and patenting activity will lead to further patent litigation.

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