IMPROVEMENTS IN VOLTAIC BATTERIES
Year: 1882

page_text: LETTERS PATENT to John Imray of Nº 28 Southampton Buildings Chancery
Lane in the County of Middlesex for an Invention of IMPROVEMENTS IN
VOLTAIC BATTERIES Communicated to him from abroad by Paul Jablochkoff,
Electrical Engineer of Paris France
PROVISIONAL SPECIFICATION left by the said John Imray at the Office of
the Commissioners of Patents on the 5th July 1882.
"
JOHN IMRAY of No 28 Southampton Buildings, Chancery Lane in the County
of Middlesex "IMPROVEMENTS IN VOLTAIC BATTERIES [Communicated to him
from abroad by Paul Jablochkoff, Electrical Engineer of Paris France]
In voltaic batteries it is usual to employ as negative element a metal such as
zinc which requires the presence of acid to produce the voltaic action. According
to this invention a more readily oxidisable metal such as sodium or potassium is
employed, so that the voltaic action is produced by the presence of air alone, pre-
ferably somewhat moist, as this is sufficient to cause oxydation. Along with the
oxidisable metal there is employed an inert conductor such as carbon, or spongy
platinum or metal gauze the porosity of which is necessary to admit air to act on
the oxidisable metal, and some porous material such as thin paper is interposed
between the two elements. The cell consisting of the two elements may be
arranged in many different ways. For example, the elements may be in the form
of flat plates clamped together with paper between them, or the carbon may be in
the form of a hollow cylinder with a rod of the sodium or other oxidisable metal
inserted in it. As the action should take place only on the surface exposed towards
the inert conductor, it is preferred to protect the exposed edges of the oxidisable
plate by varnish or other suitable coating. The battery may be rendered and kept
inactive by immersing it in oil or other liquid which does not give off oxygen, or
by placing it in a vessel charged with hydrogen or combustible or other gas devoid
of oxygen. When it has been served with oil it can be rendered active by washing
out the oil with spirit or other solvent, and its activity can be increased by
moistening the surrounding air or by covering it with moistened fabric. The

page_text: -
battery may be employed as a secondary battery, that is to say after it has operated
for a time as a primary battery during which a portion of the negative element
becomes oxidised, this oxide may be reduced to the metallic state by an inverse
current of electricity passed through the battery, and thereupon the battery can
again act as a primary battery.
By the use as described above of a metal so oxidisable as sodium, great electrical
power can be obtained from a compact and light battery, and notwithstanding the
high price of the metal, its oxidation proceeds so slowly when it is subject only to
the action of the air, that upon the whole the cost of electrical production by its
use is less than that resulting from the use of many other metals.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office, on the 4th January
1883.
JOHN IMRAY of No 28 Southampton Buildings Chancery Lane in the County
of Middlesex "IMPROVEMENTS IN VOLTAIC BATTERIES" A communication to me
from abroad by Paul Jablochkoff, Electrical Engineer of Paris France.
In voltaic batteries it is usual to employ as negative element a metal such as
zinc, which requires the presence of acid to produce the voltaic action. According
to this invention a more readily oxidisable metal such as sodium or potassium is
employed, so that the voltaic action is produced by the presence of air alone, pre-
ferably somewhat moist, as this is sufficient to cause oxydation. Along with the
oxidisable metal there is employed an inert conductor such as carbon, or spongy
platinum or metal gauze the porosity of which is necessary to admit air to act on
the oxidisable metal, and some porous material such as thin. paper is interposed
between the two elements. The cell consisting of the two elements may be
arranged in many different ways. For example, the elements may be in the form
of flat plates clamped together with paper between them, or the carbon may be in
the form of a hollow cylinder with a rod of the sodium or other oxidisable metal
inserted in it. As the action should take place only on the surface exposed towards
the inert conductor, it is preferred to protect the exposed edges of the oxidisable
plate by varnish or other suitable coating. The battery may be rendered and kept
inactive by immersing it in oil or other liquid which does not give off oxygen, or
by placing it in a vessel charged with hydrogen or combustible or other gas devoid
of oxygen: When it has been served with oil it can be rendered active by washing
out the oil with spirit or other solvent, and its activity can be increased by
moistening the surrounding air or by covering it with moistened fabric. The
battery may be employed as a secondary battery, that is to say after it has operated
for a time as a primary battery during which a portion of the negative element
becomes oxidised, this oxide may be reduced to the metallic state by an inverse
current of electricity passed through the battery, and thereupon the battery can
again act as a primary battery.
By the use as described above of a metal so oxidisable as sodium, great electrical
power can be obtained from a compact and light battery, and notwithstanding the
high price of the metal, its oxidation proceeds so slowly when it is subject only to
the action of the air, that upon the whole the cost of electrical production by its
use is less than that resulting from the use of many other metals.
A battery according to this invention may have any required number of cells,
and each of these may be of various forms. Fig. 1 is a section of a simple cell con-
sisting of a plate A of carbon to which is secured by a clamp D the plate B of
sodium, with a sheet of paper C interposed between the plates. The exposed
surfaces a a of the sodium are. varnished. Fig. 2 shews the sodium plate B between
two carbon plates A A with interposed paper C. In the arrangement shewn in
Fig. 3 the sodium B wrapped with paper or fabric C is inserted as a core in a hollow
cylinder A of carbon. Fig. 4 shews the sodium plate B between two sheets EE of
metallic gauze or fabric or perforated metal. These may be in the form of gratings
as shewn in Fig. 5 consisting of bars F held together by ties b.
As the sodium becomes oxidised producing caustic soda; this takes moisture from
the atmosphere which promotes the oxidation, and the soda solution finds its way
through the pores or perforations. A large portion of the soda in presence of
the nitrogen of the atmosphere in the pores of the carbon becomes converted into
nitrate of soda. For better starting the battery it is first dipped in a liquid,

page_text: preferably alcohol, and then on withdrawing it, its action begins. It is also of
advantage to dip in nitric acid the carbons that are to be used in the battery.
'Sufficient moisture for the action may be obtained by immersing the ends of the
interposed sheets of paper or fabric in water which soaks them by capillary action.
The carbons are preferably grooved or furrowed or made up of a number of rods
placed together.
When there is not sufficient moisture, sometimes there is formed on the sodium a
crust consisting of soda and its carbonate which introduces considerable internal
. resistance. This may be prevented by covering the surface of the sodium with a
thin layer of amalgam by applying to it oxide of mercury which becomes partly
reduced by the presence of the sodium, producing metallic mercury that
amalgamates with the sodium, and soda which is removed.. Or, otherwise the
mould in which the sodium is cast is coated internally with amalgam which adheres
to the metal cast in the mould. Another way of preventing formation of crust on
the sodium is to melt with it a metal or metalloid which can be oxidised by the air
producing oxide in gaseous form. Phosphorus answers well for this purpose and its
presence with the sodium adds to the power of the battery.
Having thus described the nature of the said invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent, I
claim:
The use for a cell of a primary or secondary voltaic battery of a negative plate
of metal or compound readily oxidisable by atmospheric exposure, in combination
with a positive plate of inert conducting porous or perforated material such as
carbon or perforated metal without exciting liquid, substantially as heroin
described.
In Witness whereof I the said John Imray have hereunto set my hand and
seal this Fourth day of January in the year of our Lord One thousand eight
hundred and eighty three.