Providing the "Fuel" for the Electric
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T"growing and successful employment of the electric vehicle —factors which are really largely interdependent—demand two main qualifications, well-designed chassis constructed of high-class materials, and reliable batteries which will give long life under comparatively arduous conditions, and in this article we deal with the latter vital components. Several well-known makers devote particular attention to these, and we give a brief resume of the leading characteristics of
their products. • The Exide-Ironclad battery, made by The Chloride Electric Storage Co., Ltd., Clifton Junction, Manchester, has an enviable reputation and is widely used in many parts of the world.
The positive plates consist of specially shaped antimonial lead rods held vertically by lead castings. The rods are surrounded by tubes of ebonite slit horizontally to permit the electrolyte to gain access to the lead oxide which fills the space between the rods and tubes.
An Exide-Ironclad Speciality.
When fully " formed," each of these cylindrical units becomes a solid but porous mass, making perfect electrical contact with its supporting rod, whilst the tubes are appreciably elastic and so allow for expansion and contraction of the active material.
Standard Exide construction is used for the negatives, but these are of a predetermined thickness to give a life as long as that of the positives.
Every user is extended an excellent maintenance service, consisting of regular visits by a skilled inspector, and each battery is supplied under a three-year guarantee.
Britannia Batteries, Ltd., Redditch, Worcester, snakes batteries of both leadacid and nickel-alkaline types for elec tric vehicles. In fact, the company claims to be the only maker producing both.
-The lead-acid is lower in first cost, B34 but the alkaline has a much longer life. In both tubular construction is employed for the positive plates. In the lead type this avoids buckling, prevents internal short circuits and reduces to the minimum the loss of active material.
The negative plates have a rippled surface allowing free access of acid, and the clear space for acid between and ' around the positive tubes permits effective circulation, whilst the strength allows a guarantee of three years.
In the alkaline battery the cells arc: practically unbreakable, and are not subject to damage by overcharging or standing idle, charged or discharged. A free inspection service is provided.
Fuller traction batteries are in the hands of many well-known operators, particularly in the municipal sphere. • They are produced by the Fuller Accumulator Co. (1925), Ltd., Chadwell Heath, Romford.
As early as 1925 the company investigated an improved form of separation to withstand vibration through road shocks, and after extensive research it adopted a triple-separation method. In this the positive and negative plates have between them glass wool, ebonite and treated wood in definite form and sequence, which act as a cushion and prevent internal short circuits.
Tests have shown that the rated capacity is maintained throughout the life, which is determined by the complete breaking This of the positive grids. It is, therefore, unnecessary ever to clean out the cells, which are guaranteed for three years.
Built throughout of steel and using an alkaline electrolyte, the Edison battery, made by Thomas A. Edison, Ltd., Victoria House, Southampton Row, London, W.C.1, is covered for traction purposes by a 10-year adjustment guarantee. It is lighter than a lead-acid battery of equivalent capacity, produces no acid fumes and is not damaged by being left charged or discharged. It is really an engineering product made by highly specialized machine tools.
Edison Steel Battery Construction.
The positive plates consist of t-in perforated tubes formed of a spirally wound steel ribbon reinforced by seamless steel rings and loaded in alternate layers with nickel hydrate and nickel flake. In the negative the iron-oxide is stamped into rectangular pockets folded from perforated nickel-steel ribbon placed in a supporting grid of similar material,, the whole 'tieing pressed hydraulically between corrugating dies.
Another long-established maker of batteries is Oldham and Son, Ltd., Denton, Manchester. Flat plates are employed, but these are separated by Port Orford cedar and reinforced with vitreous felt, giving exceptional resiliency without an increase of internal resistance. The containers ate of ebonite.
The special construction of the Kathanocle cell renders traction batteries made by the D.P. Battery Co., Ltd., Bakewell, Derbyshire, particularly suitable for traction work.
The ordinary pasted cell, owing to its high capacity, weight ratio and low internal resistance, may be the ideal from the electrical standpoint, but it is weak mechanically, particularly as regards the positive plates.
The Kathanode solution is to retain the active material by the use of a kind of felt made from spun-glass fibres, each positive plate being closely wrapped in a sheet of this material, which prevents solid material leaving the plates, permits free passage of liquid and gas, and provides sufficient elasticity.
Since the early days of electric traction the Tudor Accumulator Co., Ltd., 50, Grosvenor Gardens, London, S.W.1, has been steadily improving its products.
Tudor cells utilize a special composite separator which prevents accumulation of deposit and obviates cleaning. Felted glass wool encloses the positive plates, whilst between the wool and each negative plate is a finely perforated thin ebonite sheet and double sided ribbed-wood diaphragm. The element thus forms a compact block in the ebonite container, but possesses the elasticity necessary to withstand mechanical stresses.
Inter-cell connectors are burnt to the positive terminal posts, but to permit easy removal the connectors are secured to the negative posts by lead-covered setscrews. The connectors are flexible lead-plated copper strips.
The nickel cadmium alkaline battery has many features to render it particularly suitable for electric-vehicle work. One of the well-known makes of this type is the Ni-Fe made by Batteries, Ltd., Hunt End Works, Redditch. The containers are steel, the active material is enclosed in finely perforated steel pockets supported in steel frames, and potassium hydrate, the electrolyte, is a steel preservative.
The active material in the positive plates is nickel hydroxide, that in the negative plates, cadmium and iron. Mechanical strength and the fact that chemical change upon charge and discharge is completely reversible, automatically ensure a long life, often upwards of 10 years. The cadmium in the negatives gives the battery a comparatively low internal resistance and a good voltage characteristic, which helps to maintain speed on hills.
No amount of overcharging will harm a battery of this type. Recharging can be effected at widely differing rates.
Ten Years' Life.
A useful life of at least 10 years is claimed for Alklum steel batteries made by Alklum Storage Batteries, Ltd., Waterside Halifax. These were introduced in 1918, but a special nickel iron tubular-positive type has been developed for traction work.
The leading characteristics are light weight, coupled with the fact that the battery can be charged at widely varying rates. Containing neither lead nor acid, sulphation is impossible, and the active materials are securely held in perforated nickelled-steel tubes and pockets which cannot buckle or shed the material.
The cells are hermetically sealed, except for the filler, and no plate renewals or other repairs are needed or expected. Short-circuiting causes no damage. neither does charging in the reverse direction. No fumes are emitted, and hydrometer readings are unnecessary.
The negative plates have perforatedsteel pockets containing iron oxide, whilst the tubes on the positive side contain compressed layers of nickel hydrate and nickel flakes. Separation is by perforated ebonite and there are side insulators of this material.
A patented armoured positive electrode is used in the Young traction battery, made by the Young Accumulator Co. (1929), Ltd., Burlington Works, Malden Way, New Malden, Surrey.
Each positive plate is ppotected by an envelope consisting of a form of glass silk in conjunction with a flat sheet of perforated ebonite united by vulcanization to a porous ebonite separator. These three different items are situated each side of the plate, the whole being sealed along the sides and bottom, completely armouring the electrode. A treated-wood separator is also incorporated, with its flat surface to the negative plate and the ribs against the porous ebonite. Sealing is effected by soft rubber vulcanized to the separators, allowing for any eventual growth a,nd providing a cushion to absorb shocks.
Each cell is a separate unit in an ebonite container, the units being assembled in hard-wood trays with lifting handles.