IMPROVEMENTS IN SECONDARY GALVANIC BATTERIES OR ELECTRICAL ACCUMULATORS
Year: 1881

page_text: LETTERS PATENT to Alexander Watt, of Liverpool, in the County of Lancaster,
Fellow of the Chemical Society, and Fellow of the Institute of Chemistry,
for an Invention of "IMPROVEMENTS IN SECONDARY GALVANIC BATTERIES
OR ELECTRICAL ACCUMULATORS."
PROVISIONAL SPECIFICATION left by the said Alexander Watt at the Office
of the Commissioners of Patents on the 1st October 1881.
ALEXANDER WATT, of Liverpool, in the County of Lancaster, Fellow of the
Chemical Society, and Fellow of the Institute of Chemistry. " IMPROVEMENTS IN
SECONDARY GALVANIC BATTERIES OR ELECTRICAL ACCUMULATORS."
n
My first form of secondary battery consists of two or more plates of sheet lead
coated with a mixture of manganese dioxide, calcium hydrate, and sodium chloride
or calcium chloride, or preferably the mixture of manganous hydrate, calcium
hydrate, and calcium chloride, known in the alkali trade as "Weldon mud" mixed
with coarsely powdered carbon or coke. The plates conted on each side with the
above composition, either as a magma or compressed and granulated, are placed
in a leaden or other suitable tray containing solution of calcium chloride and piled
one upon another, each plate being separated by a layer of felt or woollen cloth.
The alternate plates are connected by strips of lead which have been left exposed
for that purpose.
My second form of battery consists of alternate layers of carbon or lead plates,
or a combination of the two, a mixture of manganese dioxide (needle manganese)
and carbon or coke both reduced to a coarse powder, and felt or woollen cloth
piled up in a tray, as in number 1, the whole being saturated with solution of
ammonium chloride (sal ammoniac) or sodium chloride (common salt) or diluted
sulphuric acid. The alternate carbon or lead plates are connected as in number 1.
A more convenient form of cell consists of an ordinary battery jar divided down
the centre by a diaphragm of porous clay, felt, cloth, or parchment. A plate is
inserted in the middle of each division, which is then filled up with the mixture
of manganese dioxide and coke, and filled with solution of sal ammoniac, common
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page_text: salt, or sulphuric acid as above. The charged porous pots (either fresh or
exhausted) of the well known Léclanché cell may even be used without further
preparation than immersing a pair of them in one of the above solutions.
Another modification of the battery consists of a porous pot containing a plate
of carbon and charged with a mixture of manganese dioxide (needle manganese)
and carbon or coke in a state of coarse powder, and placed in a leaden vessel con-
taining diluted sulphuric acid, the space between the pot and the leaden vessel
being filled with a mixture of manganese dioxide and carbon or coke, as above.
The plate of carbon forms the one pole and the leaden vessel the other pole of
the cell.
Agglomerate plates, such as used in the new form of Léclanché cell, may be
substituted for the above mixture. They may be attached to the carbon or lead
plates by india-rubber bands, or they may be wound with lead wire and insulated
in any of the above ways.
The two poles thus formed may be connected to an ordinary galvanic battery or
a dynamo-electric machine, and a current passed into the cell. On detaching the
battery or dynamo and connecting the poles of the cell with a galvanometer or
other suitable apparatus a current of electricity will be obtained of a strength and
duration proportional approximately to the time of charging.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Watt in the Great Seal Patent Office on the 1st April
1882.
ALEXANDER WATT, of Liverpool, in the County of Lancaster, Fellow of the
Chemical Society, and Fellow of the Institute of Chemistry. "IMPROVEMENTS IN
SECONDARY GALVANIC BATTERIES OR ELECTRICAL ACCUMULATORS."
My first form of secondary battery consists of lead rolled out into sheets so as
to have a large surface, and coated with a mixture of calcium hydrate manganese
dioxide and sodium or calcium chloride, or preferably the material known in the
alkali trade as "Weldon mud," from its being a product produced in the Weldon
chlorine process, mixed with about its own volume of coarsely powdered coke or
other carbon. Strips or plates of carbon may take the place of the lead plates. In
order to give the lead a greater surface than it has in sheet form I sometimes slit
it up into a bunch of fingers or thin strips joined at the top and spread out at the
bottom, and the space between them filled in with granulated lead formed by
pouring lead into water. The cell containing it is then filled up with Weldon mud
and water. In this case a porous diaphragm or a porous central cell must be used,
and the couple completed by a similar arrangement in the porous cell. In place
of the above, carbon plates and a solution of sulphate of manganese can be employed
in one cell, as the sulphate of manganese decomposes and covers the carbon with
peroxide of manganese.
My second form of battery consists of alternate-layers of carbon and granulated
manganese dioxide mixed with granulated carbon, preferably in equal volumes,
or of lead and manganese dioxide or layers arranged as follows-Mn O̟, Pb
+ C
Mn O, C MnO, Pb Mn O, C and so on, or Pb Mn0.C | Pb | NnO,C |
+ C
+
+
| |
+
+ 0
the
vertical bars being porous diaphragms. These layers can be vertical or super-
imposed with felt or woollen as a diaphragm between the plates. The exciting
liquid is preferably sal ammoniac or common salt (solution about half saturated)
or sulphuric acid diluted with nine times its volume of water. If carbon and lead
be used all the carbon plates are connected and all the lead; or if one material be
employed then the alternate plates are coupled together.
A very convenient form of cell, especially for my first form of battery, consists
of an ordinary battery jar or tank divided down the centre by a diaphragm of
porous tile, felt, or cloth. The charged porous pots, fresh or exhausted, of Leclanché
cells, may even be used without further preparation than immersing a pair of them
in one of the aforesaid solutions. If one pot be fresh and the other exhausted the
couple is charged and ready to work.
Another modification of the battery consists of a porous pot containing a plate
of carbon and charged with a mixture of manganese dioxide (needle manganese)
and carbon or coke, in a state of coarse powder, and placed in a leaden vessel con-
taining diluted sulphuric acid, the space between the pot and the leaden vessel
being filled with a mixture of manganese dioxide and carbon or coke, as above, or
simply with granulated lead. The plate of carbon forms the one pole, and the
leaden vessel the other pole of the cell.
In charging if the battery is composed of carbon and lead plates the carbon
plate must be connected with the positive pole of the charging galvanic battery or
dynamo electric machine.
I have spoken throughout of dioxide of inanganese, but it will be obvious that
in an exhausted couple there will be a lower oxide of manganese and an oxide of

page_text: lead, and the battery might actually be constructed originally with lead and lead
oxide and monoxide of manganese, but I prefer the other plan.
Having now described my Invention, and the best mode known to me of
carrying it into effect, I wish it to be understood that what I believe to be new,
and desire to protect under the herein before in part recited Letters Patent is,
1st. The application of Weldon mud or its chemical equivalent in the formation
of secondary batteries.
2nd. The combination of lead and of granulated manganese dioxide mixed
with granulated carbon in the formation of secondary batteries, substantially as
described.
3rd. The application of Leclanché pots or their mechanical equivalent arranged
in couples as a secondary battery.
In witness whereof, I, the said Alexander Watt, have hereunto set my hand
and seal, this Thirty first day of March, in the year of our Lord One thousand
eight hundred and eighty two.