You can freely build on How Car Battery Modules Combine High and Low Voltage Systems
This patent expired in 2022. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Johnson Controls Technology Co
Patent granted
2004
Expired
2022
Forward citations
46
What this patent covers
This patent describes an integrated battery module for vehicles that packs a high-voltage battery (for heavy loads like motors) and a low-voltage battery (for electronics) into one container. It includes a DC-to-DC converter to move power between the two batteries and safety switches that automatically cut power if the container is opened or a service door is accessed. The design also features specific cooling paths and apertures to move heat out of the box, ensuring both the batteries and the converter stay within safe operating temperatures.
What is now free to use
All 0 claims of US 6828755 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover battery systems that lack an integrated DC-to-DC converter.
Does not cover systems that rely solely on liquid cooling rather than the described air-flow paths.
Does not cover battery modules that do not include a safety disconnect switch triggered by opening the container or a service door.
Does not cover standalone batteries that lack a secondary low-voltage battery within the same housing.
Who is building on this today
Major automotive suppliers like Johnson Controls (now Clarios) and various Tier 1 automotive parts manufacturers have built on these concepts. Modern electric vehicle manufacturers continue to refine these integrated power electronics modules to improve energy density and safety.
Products built on expired version of this technology
Early 42V/12V hybrid vehicle electrical architectures
Integrated battery management units in modern hybrid electric vehicles
Modular automotive power distribution systems
How to cite this patent in your documentation
Johnson Controls Technology Co. US Patent 6828755. Battery system module. Granted 2004, expired 2022. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.