Lithium-ion battery technology has been described as the forklift power source of the future. Jungheinrich, however, has the technology available and ready to ship today on a bespoke pallet truck, bringing performance, environmental and cost benefits in one compact package.
The lead acid battery – invented in 1859 by French physicist Gaston Plante – has been established as the standard power source for electric-powered forklift trucks.
But, as concerns for the environment have grown, leading lift truck manufacturers have responded to customer demand by seeking, more energy efficient fuels.
For a time, hydrogen fuel cell powered trucks were thought to offer potential, but doubts surrounding the energy efficiency of the hydrogen production process allied to site supply problems and health and safety concerns over the refuelling process have curtailed its take-up as a forklift fuel.
Similarly, interest in Nickel Cadmium batteries has fallen away as a result of a number of doubts over their reliability. Nickel Cadmium batteries deteriorate when overcharged and are prone to a sudden drops of voltage at the point where the battery was previously deeply discharged, and have been shown to be susceptible to dendritic shorting – a process caused by a build-up of conductive crystals between the battery plates which can cause premature failure. Safe disposal is also a concern.
But now leading materials handling equipment manufacturer Jungheinrich believes a rival to the lead acid battery has emerged that offers a host of benefits to the truck user – Lithium-ion.
Lithium-ion batteries have been found for many years in consumer electronics and have been growing in popularity for military, electric vehicle and aerospace applications. The technology has continued to evolve, and Lithium-ion batteries – which are much smaller and lighter than the lead acid alternative – are now seen as efficient, reliable and, over their lifetime, more cost-effective than lead acid.
Lithium-ion batteries have several advantages over the traditional lead acid battery. They have a higher energy density, which means for their weight they can store more energy, while their low discharge rate enables them to retain their charge for longer.
In addition, the batteries are estimated to have almost double the cycle life (i.e. the number of times the battery can be run to flat and recharged before it wears out completely) of their lead acid counterparts.
Furthermore, Lithium-ion batteries require no maintenance. No topping-up is required, and there is zero chance of ‘over topping’ – a common cause of lead acid battery failure.
And, because the Lithium-ion recharging process is more efficient, it is some 15 per cent more energy efficient than the lead acid recharging operation. Clearly this provides a cost reduction on the electricity current draw of the premises, but more importantly, spare batteries and battery changing are no longer required, which allows the warehouse operator to make substantial savings and removes the need to invest in costly battery changing equipment.
In Spring 2011, Jungheinrich became the first forklift truck manufacturer to come to the market with a truck specifically designed and built to harness Lithium-ion’s unique qualities. Its EJE 112i Lithium-ion powered pallet truck represents one of the most significant developments in forklift truck design for many years.
“We are the first forklift truck manufacturer to go into production with a Lithium-ion powered pallet truck,” says Bill Goodwin, sales director of Jungheinrich UK.
“Jungheinrich has been at the forefront of developments in Lithium-ion technology – indeed, a prototype of the EJE 112i was first shown over three years ago at CeMAT. Other manufacturers have realised the potential of Lithium-ion and are offering trucks from their existing product range that have been merely modified to take Lithium-ion fuel cells. These so called ‘swap-out’ models do not offer the full benefits our EJE 112i’s bespoke design brings.
“The battery used to power the EJE 112i weighs just 14kg – considerably less than the lead acid batteries used on trucks of a similar capacity. The battery looks like a brief case, and its compact dimensions have enabled us to dramatically slash the size of the truck’s battery compartment and, therefore, the overall size of the truck. The EJE 112i measures 425cm – 70cm less than a comparable model with a similar capacity powered by lead acid technology.
“Because the chassis of the EJE 112i is some 18 per cent shorter than the lead acid powered equivalent, the trucks are more manoeuvrable and require less space in which to turn.
“Improved manoeuvrability also results in reduced damage to the truck itself but more importantly the environment in which the truck operates.”
The new truck weighs less too. The combined weight of the EJE 112i and its Lithium-ion battery is just 289kg – some 30 per cent less than the weight of a lead acid powered model of the same capacity. The lightness of the new model makes it suitable for loading and unloading lorries with tail lifts, as well as double-deck lorries and, of course, adds to the truck’s energy efficiency – a lighter truck requires less energy to operate.
The Lithium-ion battery charging process is quick and simple – it takes 30 minutes to deliver a 50 per cent charge and the battery is fully charged within 80 minutes. The short charging times enable more flexible truck utilisation and ‘opportunity charging’ – something that will be welcome at sites running multiple shifts.
A single charge can power the truck through a typical eight-hour shift and when it comes to recharging, a dedicated charging bay is not required. The battery is simply removed by hand from the truck and placed within a recharging docking device that can be positioned near a power supply anywhere within the building. Alternatively, an on-board charging unit can be incorporated within the specification. The simplicity of the recharging process eliminates the need for dedicated charging room personnel and means the truck is rarely out of use.
“Lithium-ion technology is no longer a forklift power source for the future – it is available today and we expect companies to be attracted by its environmental credentials as well as performance benefits,” adds Goodwin.