Thanks.
So the correct conclusion would be, for those cars which have poor
winter range, that the cell internal resistance is too low to heat the
cell ?
Also, that the cell voltage is lower during cold temps (while under
load), resulting in less Wh ?
Peri
------ Original Message ------
From: "Lee Hart" <[email protected]>
To: "Peri Hartman" <[email protected]>; "Electric Vehicle Discussion
List" <[email protected]>
Sent: 10-Sep-19 10:25:44 AM
Subject: Re: [EVDL] li ion battery in cold weather
Peri Hartman via EV wrote:
Ok, so the correct assumption would be that the Leaf and Bolt cells
don't have enough internal resistance, thus the performance stays poor
in cold weather ?
Let me try to simplify it. There are huge differences between the various types
of lithium cell constructions and chemistries. Don't assume that the same rules
apply to all of them. It's like assuming that all dogs are alike. They may all
be dogs; but there are vast differences between them!
The old Thundersky cells had very high internal resistance; more than 10 times higher
than modern cells. Since the resistance was so high, it was a more effective
"heater". They also had a very thick plastic case, which insulated and trapped
the heat. So Cedric's trick worked.
It won't work for modern low-resistance cells with good cooling. Loading a cold
cell with high current will cause a little heating (which helps). But it will
also cause significant damage from side effects. The normal chemical reactions
can't supply the current due to the cold; so this forces side reactions to take
place, damaging the cell.
Lee Hart
-- There is a computer disease that anybody who works with computers knows
about. It's very serious, and interferes completely with your work. The
trouble with computers is that you 'play' with them! (Richard Feynman)
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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