Glass cell batteries

Sebastian Foxley <bowtieseb [at] hotmail__com> writes

>I have a set of glass cell batteries to conserve. ...
>...
>The liquid contents of the cells are no longer present but there are
>white deposits over the internal components which I believe will be
>ammonium chloride and zinc chloride.  The copper alloy terminals and
>the anode are heavily corroded, the packets containing manganese
>dioxide are damaged in some cases and the rubber has degraded.
>...
>[I] would like to know if it is possible or
>advisable to do anything to stabilise the internal components. ...

Batteries are difficult. They are essentially designed to corrode,
as that is what provides the energy that is their purpose.

You can remove all the liquid component, including the salts and
corrosion (if the fluid part is all gone), in order to stop
corrosion progressing, but you are removing an integral part of the
original object in doing so. This is quite an invasive route and
generally goes against the conservation ethic.

If you go this route it would be best to make sure there is no
contact between remaining components, or put inert barriers between
them, and make sure all salts are washed out of porous components.

Alternatively you can keep the original components present, do
surface cleaning only, and just accept that degradation will
continue and the object will have a relatively short life span.

That is more of a curatorial decision, than a conservation decision,
so discuss with your colleagues what the purpose and intent of the
object is.

The rubber parts are another issue, as the rubber will continue to
degrade in the presence of light, heat, oxygen and humidity, and
will offgas sulphur which may affect other components of the
battery. Strict environmental controls (and possibly barriers or
absorbers) would be required to minimize this damage, but on the
plus side would benefit all components of the battery, not just the
rubber.

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain
Private Bag 92018
Auckland 1142
New Zealand
+64 9 306 7068


                                  ***
                  Conservation DistList Instance 25:16
                Distributed: Sunday, September 25, 2011
                       Message Id: cdl-25-16-005
                                  ***