In article ,
Ned Simmons wrote:

On Sun, 23 Mar 2008 18:09:57 -0400, Joseph Gwinn
wrote:

In article ,
Lew Hartswick wrote:

Ned Simmons wrote:

On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick
wrote:


Did "Chemistry" class ever explain how the ocean has different
layers of density that cause the sonor problems that are well
documented by submarines? I would think using your logic that
it would be one uniform solution. ????
...lew...


There are continuous inputs (e.g., rivers) and ouputs (evaporation) of
fresh water to and from the ocean which prevent it from ever reaching
equilibrium with respect to solutes, unlike electrolyte which is
thoroughly mixed before filling a battery.

Similarly, as a result of localized inputs and outputs of heat, most
bodies of water are also not in thermal equilibrium, as any swimmer
can attest. It seems reasonable that the same could be true of a
battery sitting undisturbed on a large heat sink (a concrete floor)
while air temp is fluctuating.

A-MEN!

Batteries are too small to support much of a thermocline. It takes at
least a lake to get anything that will last more than an hour or two.


I didn't see any mention of a thermocline. What's been proposed is a
temperature gradient in a battery cell that's packed with enough stuff
to inhibit convection when set on a relatively good conductor that's
at a different temperature than the ambient air.

Lew Hartwick mentioned the thermocline.

But anyway, what's the thermal conductivity of the metal battery plates,
and of the electrolyte? It has to be 1000 times greater than air, and
unless the battery is *huge*, thermal equilibrium will soon be achieved.

Joe Gwinn