I have a electric vehicle controller that has a flywheel diode that is made from
small diodes (similar to small cylinders or buttons packaged between 2 bussbars) Can anyone identify what type of diodes thes are. thanks
Identification of diodes is seldom needed. Find out how much current and what voltage the diodes in your circuit were under and just replace them with whatever you can get access to. The only really important thing which you've already stated is that these are flywheel diodes so they need to have a fast reverse recovery time.
These diodes look like a small 1/4 round by 3/8 long cyclinder. They do not have leads attached instead the metal protrudin from the end are soldered to the copper bus bar. I have saw similar diodes in golf gart battery charges used as rectifiers. But of course these need to have fast recovery characterics. I just need to know the package type or what it is called.
If they're used as rectifiers they don't need to be fast recovery. Power rectifiers seldom need to deal with frequencies greater than 60hz so recovery charactoristics aren't usually even considered.