Granted Patent
Utility
US 6,689,501 · App. 09/866,387
Composite ion exchange membrane for use in a fuel cell
Inventors:
Charles Stone, David Summers
Patented Case
View Patent ↗
Granted: Feb 10, 2004
Filed: May 25, 2001
Inventors
Charles Stone
David Summers
Assignee (at issue)
BALLARD POWER SYSTEMS INC.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.