You gave no source.
So one is better than none.
I've never heard or seen any paper that claims 104F will affect performance.
________________________________
From: Bill Dube via EV <ev@lists.evdl.org>
To: Electric Vehicle Discussion List <ev@lists.evdl.org>
Sent: Wednesday, April 1, 2015 1:13 PM
Subject: [EVDL] Temperature rating (Was: ENERDEL Battery Experiences)
The 104 F (40 C) limit applies somewhat equally
to all Li-ion chemistries. The temperature is
limited because the electrolyte boils just
slightly above that temperature. Same type of
electrolyte in all Li-ion chemistries thus the same limit.
The cell containment vessel can make a
big difference in this temperature limit,
however. Cylindrical cells can often hold
significant pressure while prismatic and pouch
cells can withstand less or perhaps no pressure.
Life a pressure cooker, the higher the pressure
of the electrolyte, the higher temperature you
can withstand. The A123 26650M1 cells (LiFePO4)
would withstand up to 100 Celsius (yes that is
correct) without damage. They weren't "rated"
that high, but they could withstand that
temperature. They were rated for 60 Celsius (140 F).
Keep in mind that the cells will age
much more rapidly at that elevated temperature.
They perform better, however, and you don't hold
them that hot for very long. You must choose the
compromise between total life-span and
performance for the specific application, which
is typical for most things in life.
I'm not sure where you are getting your
information. Better check more than one source.
Bill D.
At 10:42 AM 4/1/2015, you wrote:
>Jeff, I am not sure why performance at ambient
>temperatures should make anyone feel confident
>about a cell. LFP for instance, starts to have
>serious difficulties at 104°F if it is fully
>charged. That is certainly ambient here in
>North Carolina; and that is free air, not boxed
>up with significant amperage scooting about. I
>must tell you, I don't have an axe to grind
>here. I simply want to point out a better way
>to go. That is to get better information for
>all. And better testing with in the
>industry. ENERDEL just popped up on my radar
>is all. They have an website that is light on
>good information and I waded in. I am happy to
>see that behind the curtain they may have more
>on the ball. I have been scanning the course
>work you provided to me, and it is very
>nice. When ENERDEL discusses cycle life (around
>page 279) I can see they clearly understand the
>reactivity of the positive electrode at very
>high SOC and how temperature makes that much
>worse for the electrolyte. They clearly have
>good information to work with and probably are
>engaged with Dalhousie University or the spin
>off Novonix to get good testing done. I am duly
>impressed. I still have not figured out what
>chemistry they have chosen. From what I have
>seen so far, they speak assiduously, only in
>general terms regarding their own cells. If
>they are using some inferior chemistry and
>electrolyte package it is clearly not because
>they don't know better, so I bet they are
>OK. Provisional blessing on them until I am
>better educated. Thanks for taking the time to
>address this with me. Mike On Wed, Apr 1, 2015
>at 10:19 AM, Jeff Major via EV
><ev@lists.evdl.org> wrote: > I doubt that
>EnerDel and its customers have overlooked
>anything as basic > as performance and life at
>ambient temperatures. It appears to me that >
>Hoegberg is comparing to some float stand-by
>application and then > misinterpreting the
>presented data. But whatever. They have
>millions of > cells in the field and no
>complaints of which I am aware. > >
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