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In the public domainenergyAssigned to Sony Corporation

Lithium-ion battery

Graphite-density lithium-ion cells with PVDF-coated separators unlock longer cycle life without capacity fade for consumer batteries.

What it is

The patent describes a lithium-ion (or lithium-polymer) battery using a specific graphite anode density (1.2–1.5 g/cm³) paired with a LiNiO2 cathode density (3.0–3.3 g/cm³), with an electrolyte separated by a PVDF-coated separator that mechanically holds layers together. Matching these density targets and the PVDF-coated separator addresses degradation modes that drive capacity fade across repeated charge/discharge cycles. Until licensing rights expire, manufacturers needed permission to make batteries implementing this exact density-and-separator approach.

What you could build

Develop higher-cycle-life lithium-ion packs for e-bike, power tools, and handheld devices without paying battery-layering royalties.

Patent number
6617075
Expiration
Invalid Da
Assignee
Sony Corporation
Inventors
Takehiko Yamada, Mutsuo Azuma, Takeshi Morikawa, Yasushi Saito

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