IMPROVEMENTS IN SECONDARY OR ELECTRIC BATTERIES.
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Rankin Kennedy at the Office of
the Commissioners of Patents on the 6th January 1882.
RANKIN KENNEDY, of Glasgow, in the County of Lanark, North Britain,
REVERSIBLE
Electrician and Engineer, "IMPROVEMENTS IN SECONDARY OR
ELECTRIC BATTERIES.'
This Invention has for its object to improve the construction and action of
secondary or reversible electric batteries.
A battery made according to the Invention consists of one or more vessels, each
of any convenient shape made of wood or other suitable non-conducting material,
and capable of holding a quantity of dilute sulphuric or other suitable acid.
Immersed in the dilute acid there are plates of lead, tin, iron, or other suitable
metal or of conducting carbon, prepared in such manner as on being charged by
an electric current from a dynamo-electric machine or other source to becomes the
receptacles of oxygen and hydrogen due to the decomposing action of the current,
the oxygen being absorbed in, or in connection with, one kind of plate and the
hydrogen in, or in connection with another kind of plate. After being charged in
this way the battery is capable of being used to supply an electric current.
In preparing the plates for the battery large sheets or plates are by preference
taken to be cut up into sizes suitable for the battery after being prepared or partly
prepared. The preparatory process to be employed is similar to that used in electro-
plating and in practically carrying out this part of the Invention when the metal
to be employed is lead, a large sheet of lead is made chemically clean as is done by
electro-platers, and is carefully laid flat on the bottom of a large shallow trough
A layer of lead peroxide or dioxide is laid on the lead sheet, and the trough being
then filled with dilute sulphuric acid (one part strong commercial acid to ten parts
water) another or upper lead sheet or plate is suspended in the liquid with a space
of a few inches between it and the lower lead sheet. The upper and lower lead sheets
are connected respectively to the positive and negative poles of a dynamo-electric
machine which is driven by power so as to cause a current to pass from the upper
lead sheet through the liquid to the lower lead sheet. The strength of the current
is regulated so us to form on the lower lead she-t a fine close-grained deposit of
spongy lead and is continued until the deposit is of a sufficient thickness-say

page_text: about a sixteenth of an inch, the upper lead sheet becoming at the same time
roughened and coated to some extent with lead oxide and sulphate. The sheets or
large plates are next cut into small plates for the batteries.
The coating of spongy metal may also be obtained on the lead sheets by means
of a solution of lead sulphate, lead nitrate, or lead acetate; and other metals may
in an analogous manner be prepared for the purposes of the Invention.
The lead plates coated with spongy metal are by preference painted over with
lead dioxide which has been formed by passing chlorine through lead monoxide and
made into a paste with water and a little glycerin. The lead plates cut from the
upper sheets or plates of the preparatory process are painted over with a pasto
forined with water, glycerin, lead dioxide, and lead sulphate. The two kinds of
prepared plates are arranged in pairs, one or more pairs being placed in each
battery vessel, and each pair consisting of a plate of each kind with their prepared
sides facing each other, but separated by a sheet of non-conducting cloth or paper
or other suitable material.
In order to charge the battery the plates are connected to a dynamo-electric
machine, the positive plate having the spongy metallic conting being connected to
the negative pole, and the other or negative plate to the positive pole. The action
of the current causes bydrogen in a condensed condition to be absorbed in the
pores or interstices of the spongy metal, whilst the coating of the other plate
becomes oxidised.