Is it time for lithium ion batteries to come of age?

One of the hottest topics of discussion in materials handling is whether the many benefits offered by lithium ion batteries could be transferred to fork lift trucks.Gus Whyte, sales director - National Accounts and Systems at Hoppecke Industrial Batteries explores the battery options available.





It's safe to say that in the storage and handling industry the awareness of battery technology is not particularly high.




Traditionally, lead acid batteries have been the order of the day but two other technologies that offer various benefits look set to change the future of batteries in lifting, handling and storage equipment.




Lead acid batteries are by far the most economic and most recyclable on the market, with Hoppecke Industrial Batteries able to convert 63% of used lead acid batteries into new manufactured product.




However, standard lead acid batteries have some serious disadvantages. First, they can degrade quickly and release hydrogen and their deionised water reserves need to be topped up on a regular basis - around once every week. Also, the two main elements lead and acid - four letter words to environmentalists - are highly corrosive. And in terms of productivity, it can take between 6 and 12 hours to recharge a lead acid battery, increasing factory and warehouse downtime.




A better alternative is the fibre nickel cadmium (FNC) battery which, unlike lead acid units that need to be removed from a fork lift truck and transferred to a designated charging area, can be charged while still connected to the truck. The operator drives up to a charging unit and connects the equipment. This can take between 10 minutes and three hours depending on the rating of the charger.




A third option, and the one that was the talk of the 2011 CeMat show in Hannover, is lithium ion. As well as enabling batteries to be extremely light and small, lithium ion technology offers a maintenance free solution with no refilling required.




Other benefits include no gassing, no pollution of the atmosphere and no ventilation issues. But more importantly, lithium ion batteries offer extended life, zero degradation and higher capacity than any of the other technologies.




Still more benefits of lithium ion batteries include a much greater cycle life, a better weight to power ratio, the ability to work at very low temperatures, and the fact that they can be 'opportunity charged' very quickly. Their rapid recharge times - at very similar rates to FNC batteries - eliminate the need to keep changing batteries or to use two batteries per shift which is usually the case with lead acid units.




In terms of price, FNC batteries are around three times more expensive than lead acid while lithium ion are nine times dearer.




However, if an FNC battery was discharged to 50% and recharged, it would offer around 8,000 cycles compared to just 1,500 with a lead acid battery. And a lithium ion battery could achieve up to 10,000 cycles.




Other comparisons show that the capacity reduction on a lead acid battery is around 32% whereas FNC offers between zero and 2% degradation and lithium ion batteries don't degrade at all.




Looking to the future - and this is what excites many in the industry - because they are light and small, lithium ion batteries offer manufacturers of power pallet trucks and multi-pickers the option of designing equipment that is radically different to what is currently in use.While it's fair to say that there is certainly some resistance to such changes, it only takes one brave manufacturer to go down this road and lithium ion technology could really take off. Until this happens, however, the benefits that lithium ion offers over FNC are relatively minimal and FNC is a technology that is widely available now. (Jungheinrich has released a lithium ion model, see HSS May issue - Editor's note) Two of the biggest benefits of lithium ion units - their small size and low weight - are not relevant if fitted into existing fork lift trucks, not least because they will not save any space.More importantly, though, is the fact that the weight of a fork lift truck needs to be balanced and current models are designed to carry heavier batteries. So fitting an existing truck with a lithium ion battery would not provide any weight benefits either.




Hoppecke has carried out extensive research into lithium ion technology and predicts that in the long-term it could indeed have a bright future in materials handling. However, the technology that offers very similar benefits and is available here and now is FNC and we believe that demand from the handling and storage industry for greater productivity and reliability will see this technology leading the way for the foreseeable future.