Improvements in Thermo-electric Batteries.
Year: 1891

page_text: Date of Application, 30th June, 1891
Complete Specification Left, 29th Mar., 1892-Accepted, 30th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in Thermo-electric Batteries.
I, PAUL GIRAUD, of Chantilly, Oise, France, Doctor, do hereby declare the
nature of this invention to be as follows:-
The present application has for its object to protect certain improvements which
I have made in the production of the elements of thermo-electric batteries, and
which relate at the same time to the selection of the materials of which these
elements are composed, to their form and size, to the method of connecting same
and the manner of supporting them in the apparatus which is employed to heat one
of their extremities.
These improvements, which enable me to secure very much better results than
those which have hitherto been obtainable, will be readily understood by the aid of
the following description.
One electrode of each element is formed of an alloy of zinc, antimony, copper,
tin, silicium, and cadmium.
Certain of these metals, such as zinc and antimony, have been already
employed in the construction of thermo-electric batteries, but the experiments
which I have made enable me to employ them under more practical conditions
than hitherto.
By these means
1st. I secure the production of a greater electro-motive force, without increasing
the internal resistance of the element.
2nd. I avoid initial or primary crystallizations (immediately resulting from
casting) as well as subsequent crystallizations (produced by the heating of the
element).
The strength and duration of the elements are thus increased.
With regard to the copper, I add same
1st. To increase the mechanical resistance or strength of the alloy.
2nd. To diminish the internal electrical resistance.
3rd. To raise the melting point of the alloy.
On the other hand, the tin which enters into the composition of my alloy renders
it easier to cast, and also more homogeneous and strong.
The silicium increases the breaking resistance.
Finally, the cadmium which I employ in a suitable proportion with the
other metals above indicated, has for its object to very considerably increase the
electro-motive force of the clements.
The following are the three compositions which I employ for ordinary
construction :-

page_text: Tin
Silicium
15
12
"
33
53
دو
22
23
སྒྱུ
COMPOSITION C (FOR LARGE SIZES).
Antimony
Zinc
Cadmium
Silicium
1830 parts by weight.
960 ::
65
"*
:
52
2 ::
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It will be seen that the proportions of the various metals may be varied
considerably, and further that the copper and tin may be omitted (Composition C)
when the clements, by reason of their dimensions, afford full security as to strength;
I may even to a certain extent depart from the proportions indicated in the above
tables. The proportions in which the various metals are employed in the alloy
may, as a fact, vary according to the greater or smaller current it is desired to
produce and the dimensions of the elements. My experiments have proved to me
that, the composition of the alloy remaining the same, the electro-motive force of
an element varies:-
1st. With the three dimensions given to this element.
2nd. With the thickness (vertical dimension) of the element, the length and
width remaining the same.
Thus, for example, with the same metallic composition, the same length and the
same width, an element of two centimetres in thickness will have a greater
electro-motive force than another element of three or five centimetres in
thickness. The internal electrical resistance will also be greater in the first than
in the second case.
The object of altering the proportions of the alloy is that when the thickness of
an eleme it is increased it may retain the same electro-motive force, without
increasing its internal electrical resistance. The output is thus greatly augmented.
The following are the three sizes of the electrodes which may be most
advantageously employed to suit different cases :-
Small size: Length 0-07 m.; width 0.02 m.; height 0.02 m.
Medium size-Length 0.07 m. width 0-02 m. lieight 0.03 m.
Large size Length 0-10 m.; width 0.03 m.
It is evident that these proportions may be varied to a certain extent, as I
have explained above, I modify the composition of the alloy according to the
dimensions of the electrode.
;
height 0.05 m.
The. other electrode of each element is preferably composed of blades or plates
of tinned iron or of pure nickel; they may however be made of iron iridiumized,
platinized, or nickeled on its surface, or of ferro-aluminium.
Each of the blades or plates is united to the electrode above described by an
autogenous joint, that is to say, produced by the casting of the alloy forming this
electrode. So as to secure an efficient sealing or fixing and a large contact
surface, which, as is well known, is of the greatest importance, the end of each
blade or plate is first divided by several longitudinal slits or cuts, then the
tongues thus formed are alternately turned to the right and left, and finally
twisted.
These plates or blades are placed in a mould so that when the alloy to form the
other electrode of the element is cast in such mould that extremity of such blades

page_text: which is provided with the tongues described will be embedded therein, one blade
at the top and the other at the bottom thereof.
The part of the blade or plate which projects out from the inner end or bottom
of the electrode is folded back against this extremity, then again folded back so as
to lie against its lateral face, a sheet of asbestos board or other insulating material
being interposed between such latter face and the blade.
The top blade of one element is then connected to the bottom blade of the next
element by means of a clip and a soldered joint made carefully and by means of a
solder which does not melt at the temperature to which it is to be exposed.
This mode of connection enables any one of the elements to be replaced with
case, in case of injury, by unsoldering the two joints which unite it to the adjacent
clements in the same row, then replacing the damaged element by a new one and
making the connections again.
The extremity of each electrode which is intended to be heated is first placed in
a pulp made of asbestos powder and silicate of potash or of soda (preferably
silicate of soda), then inserted in a small cup or socket which may be produced
from sheet metal by stamping. This cup or socket serves not only to prevent the
outside of the metal from fusing, but also to distribute the heat equally all round
the part heated. The silicate and asbestos paste helps to ensure electric insulation,
at the same time that it holds the electrode in its cup or socket.
The cups or sockets carrying the elements may be insulated electrically from the
wall of the heating apparatus by a sheet of asbestos board stuck to such wall by
means of the silicate and asbestos paste already mentioned, and which is also
coated with the same paste exteriorly so that the cups or sockets adhere firmly
thereto.
The different horizontal rows of cups or sockets are insulated from each other by
rings or washers of asbestos board, and between the vertical surfaces of the cups or
sockets in the same horizontal row small pieces of asbestos board are also interposed.
It will be well understood that I may employ any other insulating material in place
of that indicated; I might, with this object, employ slag wool for example; the
cups or sockets might be fixed otherwise than by a sticky material or paste.
The system of thermo-electric elements above described may be employed in all
forms of heat producing apparatus, and which are thereby capable of heating one
of their extremities, whilst the other extremity is kept cooled by any suitable
means. I may especially arrange them around a heating stove or around steam
boilers, ovens, etc., so as to utilize waste heat; in the former case should thus
produce an apparatus capable of both heating the air of a room or other space and
of producing electricity for lighting, etc., and in the second case I should be able to
produce electricity not only free of cost but at the same time by absorbing heat
which is often disagreeable or injurious, as for example on board ship.
Dated this 20th day of Luno 1801
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Thermo-electric Batteries.
I, PAUL GIRAUD, of Chantilly, Oise, France, Doctor, 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:-
The present application has for its object to protect certain improvements which
I have made in the production of the elements of thermo-electric batteries, and
which relate at the same time to the selection of the materials of which these
elements are composed, to their form and size, to the method of connecting same

page_text: and the manner of supporting them in the apparatus which is employed to heat one
of their extremities.
These improvements, which enable me to secure very much better results than
those which have hitherto been obtainable, will be readily understood by the aid
of the following description and the accompanying drawings.
In the drawings
Figs. 1 and 2 are respectively a side elevation and a plan view of a partly
finished element such as is obtained by casting on the blades or plates >,, which
are previously placed in a mould and which constitute one of the electrodes, the
alloy which is to form the other electrode a.
Fig. 3 is a horizontal section of a group of finished elements, and shows how the
blades or plates b, b', are connected together. This figure also shows how the
elements are preferably fixed to the wall or surface which is to heat one of their
extremities (such wall being here supposed to be circular), and at the same time
how their electric insulation is ensured.
Fig. 4 is a vertical section on the line A, B, of Fig. 3, through several superposed
elements.
Fig. 5 is an end view of such elements and of the elements situated on the right
and left thereof, so as to indicate how the elements are grouped in horizontal rows.
Fig. 6 is a detail view showing how the extremity of each of the blades bor b¹ is
divided into several strips which are turned down to the right and to the left and
which are subsequently twisted, so as to obtain an effective sealing or fixing in the
electrode a and a large contact surface.
Each electrode a is formed of an alloy of zinc, antimony, copper, tin, silicium,
and cadmium.
have
Certain of these metals, such as zinc and antimony, have been already employed
in the construction of thermo-electric batteries, but the experiments which
made enable me to employ them under more practical conditions than hitherte.
By these means
1st. I secure the production of a greater electro-motive force, without increasing
the internal resistance of the element.
2nd. I avoid initial or primary crystallizations (immediately resulting from
casting) as well as subsequent crystallizations (produced by the heating of the
element).
The strength and duration of the elements are thus increased.
With regard to the copper, I add same :—
1st. To increase the mechanical resistance or strength of the alloy.
2nd. To diminish the internal electrical resistance.
3rd. To raise the melting point of the alloy.
On the other hand, the tin which enters into the composition of my alloy renders
it casier to cast, and also more homogeneous and strong.
The silicium increases the breaking resistance.
Finally, the cadmium, which I employ in a suitable proportion with the other
metals above indicated, has for its object to very considerably increase the electro-
motive force of the elements.
The following are the three compositions which I employ for ordinary
construction -
.1

page_text: Cadmium
Silicium
رو
وو
65
2 "
"
"
"
It will be seen that the proportions of the various metals may be varied con-
siderably, and further that the copper and tin may be omitted (Composition C)
when the elements, by reason of their dimensions, afford full security as to
strength; I may even to a certain extent depart from the proportions indicated in
the above tables. The proportions in which the various metals are employed in
the alloy may, as a fact, vary according to the greater or smaller current it is.
desired to produce and the dimensions of the elements. My experiments have
proved to me that, the composition of the alloy remaining the same, the electro-
imotive force of an element varies :-
1st. With the three dimensions given to this element.
2nd. With the thickness (vertical dimension) of the element, the length and.
width remaining the same.
Thus, for example, with the same metallic composition, the same length and the
same width, an element of two centimetres in thickness will have a greater electro-
motive force than another element of three or five centimetres in thickness. The
internal electrical resistance will also be greater in the first than in the second
case.
The object of altering the proportions of the alloy is that when the thickness of
an element is increased it may retain the same electro-motive force, without
increasing its internal electrical resistance. The output is thus greatly augmented..
The following are the three sizes of the electrodes a which may be most.
advantageously employed to suit different cases :--
:
Small size Length 0.07 m.; width 0.02 m.; height 0.02 m.
Medium size Length 0.07 m.; width 0.02 m.; height 0.03 m.
Large size Length 0-10 m.; width 0.03 m.; height 0.05 m.
It is evident that these proportions may be varied to a certain extent, as I have
explained above, I modify the composition of the alloy according to the dimensions
of the electrode.
The other electrode of each element, is preferably composed of blades or plates
of tinned iron or of pure nickel b, they may however be made of iron
iridiumized, platinized, or nickeled on its surface, or of ferro-aluminium.
Each of the blades or plates b, 64, is united to the electrode a by an autogenous
joint, that is to say, produced by the casting of the alloy forming the electrode.
So as to secure an efficient sealing or fixing and a large contact surface, which,.
as is well known, is of the greatest importance, the end of each blade or plate is
first divided by several longitudinal slits or cuts, then the tongues thus formed are
alternately turned to the right and left, and finally twisted, as is clearly shown in
Figs. 3, 4 and 6.
The part of the blade or plate which projects out from the inner end of
the electrode a is folded back against this extremity, then again folded back so as

page_text: to lie against its lateral face, a sheet of asbestos board or other insulating material
being interposed between such latter face and the blade.
The blades or plates and are then connected together by means of a clip and
a soldered joint made carefully and by means of a solder which does not melt at
the temperature to which it is to be exposed.
This mode of connection enables any one of the elements to be replaced with
ease, in case of injury, by unsoldering the two joints which unite it to the adjacent
elements in the same row, then replacing the damaged element by a new one and
making the connections again.
The extremity of each electrode a which is intended to be heated is first placed
in a pulp made of asbestos powder and silicate of potash or of soda (preferably
silicate of soda), then inserted in a small cup or socket, which may be produced
from sheet metal by stamping. This cup or socket serves not only to prevent
the outside of the metal from fusing, but also to distribute the heat equally all|
round the part heated. The silicate and asbestos paste d helps to ensure electric
insulation, at the same time that it holds the electrode in its cup or socket.
The cups or sockets c carrying the elements may be insulated electrically from
the walle of the heating apparatus by a sheet of asbestos board stuck to such
wall by means of the silicate and asbestos paste already mentioned, and which is
also coated with the same paste exteriorly so that the cups or sockets c adhere
firmly thereto (see Figs. 3 and 4).
The different horizontal rows of cups or sockets c are insulated from cach
other by rings or washers of asbestos board g, and between the vertical surfaces of
the cups or sockets in the same horizontal row small pieces of asbestos board hare
also interposed. It will be well understood that I may employ any other insulating.
material in place of that indicated; I might with this object, employ slag wool
for example; the cups or sockets a might be fixed otherwise than by a sticky
material or paste.
The system of thermo-electric elements above described may be employed in all
forms of heat producing apparatus and which are thereby capable of heating one
of their extremities, whilst the other extremity is kept cooled by any suitable
means. may especially arrange them around a heating stove or around steam
boilers, ovens, etc., so as to utilize waste heat; in the former case I should thus
produce an apparatus capable of both heating the air of a room or other space and
of producing electricity for lighting, etc., and in the second case I should be able to
produce electricity not only free of cost but at the same time by absorbing heat
which is often disagreeable or injurious, as for example on board ship.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is: :-
1. The manufacture of one of the electrodes a of the elements of a thermo-
electric battery of an alloy formed of the metals hereinbefore specified, and
employed substantially in the proportions and with the object indicated; two of
the metals indicated being capable, as pointed out, of being omitted in certain cases.
2. The forms and proportions which 1 preferably give to the electrodes a, as
indicated in above description and on the accompanying drawings, in combination
with the employment for their manufacture, of an alloy of which the composition
varies according to the dimensions of the electrodes, substantially as specified.
3. The manufacture of the parts 6, 61, constituting the second electrode of each
element of a thermo-electric battery, of blades or plates of tinned iron, pure nickel,
ferro-aluminium, or of iron iridiumized, platinized or nickeled on its surface,
substantially as specified.
4. The formation of a joint on the blades or plates b, b¹, to permit any of the
elements being replaced in case of injury, substantially as specified.
5. The making of the joint referred to in Claim 4 by a clip and a solder joint,
substantially as specified.

page_text: 6. With a view to strongly securing the blades or plates b, b', in the two
extremities of the clectrode a and giving them a large contact surface with the
alloy of which the latter is formed, dividing the end of each of these blades or
plates b,, into several tongues which are turned over alternately to the right and
to the left, then twisted on themselves, and the placing of the end thus prepared
in the mould which is to receive the alloy of which the electrode a is composed,
before the casting of such alloy, in such a position that the body of the plate or
blade is in a plane parallel to the length of the electrode a and in the direction of
its length: the blade or plate being afterwards turned down laterally, then, in so
far as the blade or plate only is concerned, bent again against the lateral face of
the electrode a, from which. it is insulated by a sheet of asbestos board or other
insulating material, substantially as specified.
C
7. The cup or socket c in which the inner end of each element enters and is fixed
and from which this element is electrically insulated by means, for example, of a
paste or composition formed of asbestos powder and of silicate of soda or of potash,
which at the same time serves to fix it; such cup or socket serving not only to
hold the element, but also to uniformly transmit the heat to the whole of the
heated part, substantially as specified.
8. The electrical insulation of the cups or sockets c by means of a thickness of
insulating material interposed between them and the surface which gives out the
heat necessary to the operation of the battery, and also between the horizontal
faces and the vertical faces of the cups or sockets forming part of the different
rows, such insulating material consisting preferably of asbestos board impregnated
or coated with a composition or paste composed of asbestos powder and of silicate
of soda or of potash, which forms a paste which fixes the elements at the same time
that it insulates same, substantially as specified.
9. The employment of slag wool also with the object of insulating the elements,
substantially as specified.
10. The application of the thermo-electric elements described to any surface
giving off heat, and especially round heating stoves of any suitable construction, so
as to obtain at the same time both heat and also electric energy for lighting or
other purposes, or round ovens, etc., so as to utilize waste heat.
Dated this 29th day of March 1892.
ALLISON BROS.,
Agents for the Applicant.