Invalidating a solid-state battery patent by mapping polymer synthesis to 1980s cosmetic chemistry.
A Fortune 500 EV manufacturer was targeted by a patent asserting a novel cross-linked siloxane-polyurethane block copolymer used as a binder in solid-state battery electrodes.
The patent claimed this specific polymer structure was novel because it uniquely provided:
Cut-off Date: Prior to March 2014
Battery patents use terms like "solid electrolyte interface," "anodic binder," and "ionic conductivity." Standard Boolean searches combining the polymer structure with battery terminology yielded zero results before 2014.
Previous search firms restricted their queries to H01M (Processes or means for direct conversion of chemical energy into electrical energy). If the polymer was synthesized in a different industry, it would never appear in these classes.
We stopped looking for "battery binders." We abstracted the claim down to its core chemical synthesis: reacting specific isocyanates with siloxane polyols.
We searched for this exact synthesis method across all industries. We discovered this polymer structure is heavily used as an "emulsion stabilizer" in cosmetics.
To prove obviousness (103), we found a secondary 2005 electrochemistry paper suggesting cosmetic-grade siloxane polymers exhibit excellent ionic transport when doped with lithium.
Our native-language researchers uncovered a 1988 French patent (FR'892) detailing the exact synthesis method and chemical structure of the claimed copolymer.
The patent was filed by a major cosmetics company. The polymer was formulated to create a long-lasting, heat-resistant lipstick that repelled moisture—providing the exact same thermal and hydrophobic properties claimed in the modern battery patent.