Cathode material and secondary battery using the same
CA 2107440 C · Owner: Okada, Shigeto · Inventors: Shibata, Masasi; Ichimura, Masahiro; Arai, Hajime
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cathode material made of anhydrous ferric sulfate with a hexagonal crystal structure is presented for use in a secondary battery which generates a stable open-circuit-voltage of about 3.6 volts and offers a recharge cycling capacity of over 100 times. The cathode material is obtained by heating hydrous iron sulfate material in a temperature range between 250 and 600 °C to remove the water of crystallization. The secondary battery made with this cathode material provides a long-service life and a stable output voltage economically because the, starting material, iron sulfate is abundantly available, at relatively low cost.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed September 30, 1993 and granted June 23, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 30, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 30, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.