On 4/16/20 6:32 PM, Michael Ross via EV wrote:
As shown by the research at Dalhousie, 16000 cycles is meaningless if the
conditions are watered down.
That kind of cycle count is falsely impressive, and a huge waste of time
and resources.
Assuming you are not referring to a 1C discharge rate to be "watered
down" OR a 100% discharge, what conditions ARE you referring to?
Are there any useful testing standards becoming a tradition? As in
standards that actually stress the cells in some way other than cycle count?
Part of Tesla's success with cell life comes from actually breaking cells
and trying to make them better.
On Thu, Apr 16, 2020 at 6:19 PM Bill Dube via EV <ev@lists.evdl.org> wrote:
The A123 systems 26650 cylindrical cells have a _huge_ cycle life.
Way over 5000 cycles at a 1C rate. 100% SOC discharge. (They have cycled
a 26650 cell more than 16,000 times and still have greater than 50%
capacity.)
The main trouble with higher rates is the elevated cell temperature
while testing. Higher rates => higher temperature => shorter life span.
The issue becomes entangled with calendar life. Calendar life is a steep
function of temperature. Exponential, actually.
Bill D.
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
ARCHIVE: http://www.evdl.org/archive/index.html
INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
