It is a current collector built from a polymer substrate carrying thin metal or conductive layers, rather than a solid pure metal foil, aimed at weight saving and safety benefit in battery cells. Because the structure is built from a lamination step, a coating or metallisation step, and sometimes a welding or tab-joining step, relevant prior art sits across several IPC subclasses rather than solely inside battery-specific classes like H01M. A search limited to battery-cell classifications will miss lamination, coating and joining claims that cover the same physical product from a different angle.

The ranking in this dataset covers 100 companies, counted in patent families, and includes automakers, steel and materials companies, battery cell makers and semiconductor-equipment firms. The leader holds 82 records, but the top 5 combined account for only 6.5% of the 4,241 records in scope and the top 10 for 11.0%, so no single company dominates. That low concentration means competitive tracking needs to follow a broad set of filers rather than a handful of dominant portfolios.

Filing activity peaked in 2022 at 171 records and, across the last complete three-year comparison (2021 to 2024), volume moved from 147 to 138 filings, a -6% change. That is best read as a steady, mature filing pace rather than either rapid growth or a genuine decline. Publication lags filing by roughly 18 months, so the most recent one to two years in any trend chart will always look artificially low and should not be used to call a slowdown.

Relative to the dense H01M and B32B claim space, areas such as through-plane resistance test methodology, tab-welding joint design specific to composite foils, in-plane conductivity gradient control and sheet-metal working of laminated structures carry comparatively thin coverage in this dataset. These are process- and testing-adjacent branches rather than core cell-chemistry claims, which is often where they get overlooked by filers focused on battery classifications. A first claim in one of these areas would typically need to tie a specific structural feature to a measurable process or test outcome to stand apart from the existing lamination and coating art.

That record and others among the most-cited in this dataset relate to semiconductor device peeling-off and manufacturing methods and to LED retrofit lamps, and their high citation counts largely reflect their age and foundational role in adjacent semiconductor and lighting patent families within this searched corpus. Citation volume here is a signal of historical influence inside the dataset, not a ranking of current commercial relevance to composite current collectors specifically. Newer, less-cited filings such as the composite current collector application from Yangzhou Nanopore are often more directly on-point for current freedom-to-operate work.