The dataset shows filings rising from 813 in 2017 to a peak of 1,917 in 2023, with the prior year, 2022, already nearly as high at 1,799 - meaning growth had flattened before the visible peak. Recent-year momentum data shows every major assignee tracked posting a year-on-year decline into the latest period, several exceeding 80%, which points to a broad slowdown rather than one company's retreat. Some of the drop in the most recent one or two years is also a publication-lag artefact, since filings typically take around 18 months to appear in the record, so the true 2025-2026 filing volume is understated here.

Samsung SDI, CATL (China's Contemporary Amperex Technology), LG Energy Solution, SK On (formerly SK Innovation's battery unit) and Toyota all appear as active filers in the recent-year momentum data, with Samsung SDI, CATL and LG Energy Solution the largest by recent volume. Ownership also clusters inside corporate groups: the strongest co-assignee pairings are SK Innovation with SK On, Panasonic with Sanyo, and LG Energy Solution with LG Chem, reflecting joint-venture or internal R&D filing structures rather than cross-licensing between separate companies.

A composite current collector replaces or augments the traditional solid metal foil with a layered structure, typically an organic or polymer support layer coated with a thin metal conductive layer, aimed at reducing weight and improving safety under mechanical stress such as puncture. CATL's US20220085384A1 is a representative example, claiming a specific brittleness parameter range for such a structure. These are filed as distinct inventions from electrode active-material patents because the collector's mechanical and conductive properties are treated as a separate engineering problem, governed by different IPC classes such as H01M50 and C23C14.

The IPC composition shows H01M (batteries and cells) accounts for 19,989 of the 24,786 families, roughly eight in ten, while capacitor-related claims under H01G sit at 1,133 and coating-process classes such as C23C and B05D each hold under 320. That gap suggests capacitor-grade composite foils, electroplated surface finishing under C25D, and carbon-primer coating processes are comparatively under-claimed relative to core battery-cell collector structure, though a full freedom-to-operate check is still needed before assuming any branch is genuinely open.

Citation counts in this dataset are useful but skewed toward older filings simply because they have had more years to accumulate citations; the most-cited record here, US20140170488A1, has 556 citations partly for that reason. A high citation count signals a patent's historical influence on later filings and is a good starting point for a prior-art search, but it should not be read as a measure of which technology is most commercially important today. Newer filings in fast-moving sub-areas like thickness reduction or puncture safety may be highly relevant despite having far fewer citations so far.