"Ronald Raygun" wrote in message . uk...
Capt. Neal® wrote:

Again, electrons don't move THROUGH the battery.

Correct. Electrons DON'T move through the battery, but charge does.

They only reside
on physically separated plates via chemical reaction (not a circuit).

Incorrect. That's what happens in a capacitor, but not in a battery.

In a capacitor, electrons are stored on one plate and "holes" on the
other, and no electrons move THROUGH the capacitor. Nevertheless charge
APPEARS to move through it because it goes in via one wire and out via
the other, but really the charge is only stored on the plates and does
not travel across the gap. When you DIScharge a capacitor, the charge
comes back out again, but still no charge travels directly from one
plate to the other within the unit.

A battery is different. It also stores charge, but not by accumulating
more and more electrons on one plate and holes on the other, but rather
by arranging for chemical changes to occur not only on both plates, but
also in the electrolyte.

True.

As shown in hyperphysics.phy-astr.gsu.edu/hbase/electric/leadacid.html
which you pointed us to, a charged battery starts off with the electrolyte
of sulphuric acid, i.e. a soup of negative sulphate ions and positive
hydrogen ions, and with PbO2 on one plate and Pb on the other. When
the plates are connected via an external circuit, the sulphate ions are
absorbed equally on each plate, in a reaction which at the Pb end
generates PbSO4 and liberates electrons and H+ ions, and at the PbO2 end
also generates PbSO4 and absorbs electrons and H+ ions. To sustain this
reaction, the electrons travel from one plate to the other on the outside
of the battery, via the circuit wire, while the H+ ions travel from one
plate to the other internally, through the electrolyte.

Therefore charge does travel through the battery. We have a complete
circuit, with external flow of electrons and internal flow of H+ ions.

There's where I disagree. Charge does not 'travel through' the inside
of a battery. There is no conductor only chemical reactions that change
the composition of the plates. Depending on whether the battery is
being charged or discharged these reactions run one way or the other.

Note, I said the reactions run one way or the other. I did not say the
electricity flows one way or the other. There is a difference which
all you naysayers fail to comprehend. Chemical reactions change
the plate composition. Plate composition is responsible for the current
that is noted in the circuit *outside* the battery. There is no corresponding
circuit inside the battery. If there was the battery would immediately
short out internally.


During charging, the same thing happens, electrons are "pumped" back
into one plate and sucked out of the other, which causes the hydrogen
ions to travel through the electrolyte in the opposite direction to
that in which they travelled while the battery was being discharged.


Nothing in the way of current travels back and forth in the electrolyte.
The electrolyte is there only as a medium for chemical reaction not as
a highway or path for electrons to travel.

CN