Improvements in Thermo-electric Batteries or Piles.
Year: 1899

page_text: Date of Application, 10th Apr., 1899-Accepted, 2nd June, 1899
COMPLETE SPECIFICATION.
Improvements in Thermo-electric Batteries or Piles.
I, JOSEPH MATTHIAS, of 55, Gymnasiums-strasse, Stuttgart, in the Empire of
Germany, Telegraph Secretary, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In thermo-electric batteries or piles every element or cell is composed, as is well
known, of two different metals or metallic alloys. If these are chosen so that
they are able to produce the greatest possible electrical action, they being therefore
as widely separated as possible in the electro-chemical series, the physical properties
of the metals or metallic alloys will then differ relatively more from one another
than in the case where only a slight action is produced, and the metals in question
are situated nearer together in the electro-chemical series. If for instance there
is taken for the composition of the electrodes on one side German silver and on
the other side an alloy composed of two parts of antimony and one part of zinc
a greater electrical action is obtained. But the fact has to be considered that
whilst the first electrode is hard, the second has the disadvantage of greater
fragility. This extreme fragility or liability to fracture has hitherto hindered the
general application of such alloys to thermo-electrical purposes, however much it
may have been desired to make use of their high electro-motive power. If besides
this, (as in the case of the electrodes described in the following description) their
special form is such as to increase their liability to be broken, their application
would be absolutely impossible unless special protective means are employed.
The present invention consists of an improvement in thermo-electrical batteries
or piles by which great firmness or support is imparted to the fragile electrode,
thereby permitting an unlimited application and durability of the elements and
at the same time reducing the resistance to a minimum by reason of the special
form, arrangement and connection of the electrodes, uniting the separate elements
in very large numbers in a relatively small space and permitting an intense
cooling action being applied to the side of the electrode furthest from the source of
heat.
In the accompanying drawing, Figure 1 is a perspective view of the hard electrode,
Figure 2 a similar view of the fragile electrode, Figure 3 a vertical section through
a part of the battery, Figure 4 a perspective view of the fragile electrode sur-
rounded by a protecting cover, Figure 5 a vertical section through a part of the
battery when the protecting cover Figure 4 is in use. Figure 6 a view of the
battery from below, and Figure 7 a view of the battery from above.
The separate electrodes have in their outer configuration the form of prisms and
are placed side by side; the two electrodes of an element differ however in form from
one another, in so far, that the electrode a, composed of hard metal, has a projec-
tion on the side which is to be turned towards the source of heat, the size of
which projection exactly corresponds with the bottom surface of the electrode
composed of fragile metal, this electrode being as much shorter than the hard"
electrode a as the projection g is thick, so that the hard electrode is as long as g
and 6 together. The sides of the electrodes a which are turned to the source of heat
are preferably arranged so that their surfaces will be of such a size as to completely

page_text: fill up that side of the battery. By this means the elements on that side which is
turned towards the source of heat offer no spaces by which the hot air might pass
to the other side. In the figure the form of a rectangle is shewn as an example
the length of which is twice as long as the width whilst the electrode a above the
projection is square in cross section, as is also the lower part of the electrode b.
This lower part of each of the electrodes (disregarding the projection 9) has
approximately the form of a cube. The upper part of the electrode a is formed into
a large number, say 9, of tapering points, whilst the fragile electrode is pre-
ferably formed into two wedge-shaped projections k. The object of forming the
electrodes into these tapering points is to enable the electrode to be subjected in
close contact as much as possible to the circulation of cool air whereby the difference
of temperature between the electrodes is increased. By thus forming the electrode
the resistance of each separate element may also be reduced as desired.
The connection between the electrodes a and b of an element is made by casting
the metal of the fragile electrode upon the hard one, the projection g of the latter
being provided with a hard metal knob m which, before the electrode b is cast upon
it, is covered with the thinnest possible layer of solder. A close connection of the
electrodes a and is thus effected, and a firm support for the latter is also
provided..
The connection of the electrodes of the adjoining elements with one another is
effected by means of strong bridge pieces made of good conducting metal
difficult to melt. This bridge piece is made as follows: the pointed ends of both
electrodes covered for about 10 millemetres with the thinnest possible layer of
solder, and the connecting bridge piece is then cast over them, a close connection
of the bridge with the ends of the electrodes being thereby established, and the
resistance to the current permanently reduced to a minimum. The elements
are separated from one another by insulating layers. By this arrangement the
fragile electrode comes between the strong parts of the projection and the
bridge d and is therefore entirely protected both above and below and has a con-
tinuous and extremely firm support. The easily melted metal of the fragile
electrode is protected from too great a heat by the hard base projection.
In some cases where it is desired to give increased protection to the sides of
the fragile electrode the metal thereof can be surrounded with a prismatic or other
suitably shaped clay or earthenware cover e, open at its top and bottom, which
Jatter may rest on the projection of the hard electrode which in this case is
provided with a spur for the reception of a connecting pin f which passes through
it and the clay cover into the electrode a. The projection 9 as well as the pin f
are covered with the thinnest possible layer of solder and the metal for the
electrode b may be introduced in a molten condition into the clay cover and in this
way bcomes closely united, by means of the solder, both with the projection g and
with the pin f. In this case the clay or earthenware cover c is not filled up to its
top edge with the metal of the electrode but only to the edge of the opening g
situated towards the side of the adjoining element, so that the electrode is shorter
than in the case of Figure 3 by the height of this opening. This opening y
serves to receive the connecting bridge piece d, which also is formed by casting.
The connection between this bridge piece d and the electrode 6 is effected in casting
the electrode band the bridge piece d, the connecting pin e (also previously
covered with the thinnest possible layer of solder) being surrounded by the molten
metal. This pin holds with its head and neck in the bridge piece, its lower portion
which extends into the alloy being forked as shewn so that its four branches pass
through the walls of the clay or earthenware cover c and are bent over upwards or
downwards outside thereof, and no undue strain is put upon the fragile mass
of metal. The bridge is thus held by means of the four branches to the walls
of the cover c and a firm and close connection is created.
In order to facilitate the necessary cooling, instead of dividing the fragile
electrode into two bridge-shaped branches, as proposed in the first arrangement,
the electrode b may be provided with a number of air holes which pass through

page_text: its upper part parallel with the pin f. In making the electrode the holes in the
walls are formed by the employment of cores, which are afterwards removed.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I déclare that what
I claim is:-
First. In thermo-electric batteries or piles the arrangement of the fragile and
easily melted electrode which requires protection in such a manner that it rests
on a projection of the other electrode, on the side which is turned towards the
source of heat, and in this manner is withdrawn from the direct action of the
radiating heat substantially as described with reference to the drawings.
Second. In thermo-electric batteries or piles the arrangement of a strong
metallic bridge-piece upon the forked ends of electrodes of a pointed form to
facilitate cooling so that it connects each two adjoining elements.
Third. In thermo-electric batteries or piles according to Claim 1, the forming of
a clay cover round an electrode centre piece for the purpose of protecting the sides
of the electrode requiring protection, which clay cover is provided with holes at
the side, with which coincide holes passing through the electrode centre piece
together with the connection of the metallic bridge piece, conducting to the next
element, with the electrode inside the clay cover in such a manner that the
forked branches of a pin, situated with its head shaped end inside the bridge
piece, are made to pass through the electrode and through the clay walls, on the
outside of which they rest with their ends bent over.
0711 Ja of Manch 1809
day of March 1809
J. MATTHIAS.
Per W. H. Beck,
Agent, 115, Cannon Street, London, E.C.