By David Goss, Technical Manager, British Industrial Truck Association (BITA).
The majority of warehouse trucks are currently battery powered, and those are overwhelmingly of the traditional lead acid type. Lithium ion (Li-ion) technology offers significant advantages and has been around for a number of years, but take up has been very slow.
The benefits of Li-ion are well understood:
• Fast, energy efficient, charging from any point in the discharge cycle promotes ‘opportunity charging’, the truck being topped up during breaks and at shift changeover. This is especially beneficial in multishift operations where expensive assets, exchange batteries or whole trucks, otherwise have to be duplicated.
• Longer life with less degradation.
• Virtually maintenance free.
• Charging doesn’t generate hydrogen gas, simplifying charging station safety requirements.
Currently the Li-ion purchase price is higher, whilst this will improve as sales volumes increase, it is necessary to look at whole life costs to make an informed decision.
Moreover, if you’re expanding an existing facility there are some barriers to adoption of Li-ion:
• The infrastructure requirements are very different. For instance, although more energy efficient overall, rapid charging draws a very high current.
• Mixed fleets present greater operational and maintenance challenges, and there are benefits in utilising a single power type across the site.
It has been suggested that Li-ion isn’t suitable for counterbalance type trucks because their lighter weight requires a corresponding increase in the mass of the counterbalance.
However, this argument ignores two important facts: firstly, the overall weight isn’t being increased, so, whether the mass is in the battery or integral to the truck, the power requirement doesn’t change, and secondly, the majority of trucks currently on the market were designed for lead acid batteries, with the Li-ion option added afterwards. This means design optimisation, taking full advantage of the opportunities offered by the new technology, is only beginning to take place.
Whilst the recent UK Government proposal to end the sale of new petrol and diesel engine cars and vans by 2040 is not aimed at industrial trucks, it may provide significant spin off benefits aiding Li-ion uptake. Volume manufacture drives down costs and a mass market solution to recycling Li-ion will also be required.
Interestingly, the infrastructure requirements of this proposal may also promote adoption of fuel cell technology as a viable alternative to the battery electric truck, for instance by providing readily accessible hydrogen fuel supplies.