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Lithium-ion technology

Lithium-ion technology − The end of the lead-acid battery CEMAT ASIA In 2011, Jungheinrich placed a serial truck, the EJE112i/114i, with lithium-ion technology on the market. Now, the Hamburg-based intralogistics group develops and produces not only trucks but also electrical/electronic systems including energy storage. The Energy & Drive Systems division of the company employs around 270 employees focused on the development and production of control devices, battery chargers and lithium-ion batteries. This field is one of Jungheinrich’s fastest growing business areas. Energy efficiency is one of the most important topics of our time. While electric mobility is still largely a dream of the future for motorists, intralogistics has long be a pioneer when it comes to electric drive systems. In warehouses the world over, there is a noticeable trend towards electric drive systems and away from internal combustion engines. Jungheinrich alone constructs and sells more electric trucks every year than the entire German automobile industry as a whole. Until recently, trucks operated almost entirely with lead-acid batteries, but lithium-ion technology has begun to grow disproportionately, and the general trend towards electric drive systems is accelerating at pace. Author: Dr. Oliver Lücke, Member of the Board of Management Engineering Jungheinrich AG, Hamburg Jungheinrich systems have the advantage of the batteries, battery chargers and trucks being perfectly coordinated to one another. A key factor in this is the ongoing intercommunication between the individual components. All in all, this leads to a clear increase in the performance of electrically operated trucks and in turn, the attractiveness of the technology for cost-optimized warehouse use. The performance and energy density of lithium-ion batteries means that in the future, application areas where the use of electrical drive systems would once have been unthinkable, could see electrified trucks being used. High reliability and service life Lithium-ion batteries are complex systems which, alongside battery cells, also incorporate a sophisticated electronic system which ensures safe and reliable operation. Each individual lithium-ion cell of a battery is continuously monitored to ensure that its temperature, voltage and charge status are optimal. This information is monitored by the Battery Management System (BMS), which ensures optimum and safe performance at all times. This offers the user maximum performance with high reliability and an excellent service life. Service life: Jungheinrich batteries achieve 3000 full cycles (full charge and discharge) and considerably more partial cycles. By comparison, lead-acid batteries tend to achieve just 900 to 1200 cycles, meaning that lithium-ion batteries have a life cycle that is at least three times longer. Looked at differently, when the classic lead-acid battery reaches the end of its service life after around four years, a lithium-ion battery would still have only reached half of its expected service life. Jungheinrich offers full integration of truck, lithium-ion battery and battery charger, all from a single source. This allows for a full WORLD OF INDUSTRIES – INTRALOGISTICS & DISTRIBUTION 5/2017

ange of innovative solutions. In the future, the customer will be able to see the status of all batteries or measure the energy consumption and efficiency of individual trucks or the entire fleet at the push of a button. Other energy management solutions include calling up the status of a battery on the go from a smartphone or controlling battery charging and the availability of battery chargers over an entire fleet so as to avoid waiting times and network peaks, thus ensuring optimised customer use. Safety is often seen as critical when it comes to lithium-ion technology. Jungheinrich deliberately uses the safest cell chemistry on the market, incorporating lithium iron phosphate. These cells have become the first choice for the logistics industry when it comes to environmental compatibility, the use of raw materials (no cobalt), temperature stability and service life. Cost-efficient in the balance sheet The crucial question is when does the switch to lithium-ion technology begin to pay dividends for the customer? Lead-acid batteries are, after all, still available and so far at least, are cheaper to buy. But we are confident that the extra initial investment outlay is worth it. If you look at the Total Cost of Ownership (TCO), many different applications would be well advised to switch over to lithium-ion technology. Why? Just looking at the individual charging and discharging cycles, the use of lithium-ion batteries is much more cost effective than the use of traditional lead-acid batteries. The example TCO calculation determines the overall system costs of lithium-ion and lead-acid batteries per month based on a common Jungheinrich product, the ECE horizontal order picker with corresponding energy source (24 V 240 Ah). In a first shift, user values are entered into the calculation template, which are industry and location specific. For the Jungheinrich ECE model, a comparison is made between the 24 V 240 Ah lithium-ion battery and the „In the balance sheet, lithium-ion-batteries are more cost effective than lead-acid batteries” 24 V 465 Ah lead-acid battery. The significant differences between the two battery types are in terms of the purchase and operating costs. A lithium-ion battery costs approx. 75 percent more than its lead-acid equivalent. The higher purchase costs are, however, recovered quite quickly thanks to the lower operating costs of the lithium-ion battery. For example, the time-intensive daily battery replacements which, in this example are calculated rather conservatively at 6 minutes per replacement, are no longer necessary. In addition, with lead-acid batteries, water needs to be added to the battery at least once a week, depending on the operating conditions, which takes around 5 minutes each time. In order to preserve the performance service life of the battery, regular battery cleaning is also recommended, to take place every 6 months. In addition, the total cost calculation for lead-acid batteries also takes into account the comparatively low energy efficiency on charging (charge factor) and the considerably lower service life. Reliable, flexible, energy-efficient A benefit of lithium-ion batteries that must not be underestimated is the higher energy efficiency during use. When compared to leadacid batteries, a much greater proportion of the braking energy is About Jungheinrich Jungheinrich is one of the world’s leading companies in the industrial truck, warehousing and material flow engineering sectors. As a manufacturing service and solution provider in the field of intralogistics, the company, based in Hamburg, Germany, supports its customers with a comprehensive product range that includes forklift trucks, shelving systems, services and consulting. The Jungheinrich share is traded on all German stock exchanges. stored in the battery. On the one hand, this reduces energy costs for the customer while on the other hand, a lithium-ion battery is capable of using a much lower capacity without sacrificing range or performance. Taking into account all of these factors and the higher service life of the lithium-ion battery, total costs per month come out at approx. €100 for lithium-ion batteries compared to €145 for their lead-acid counterparts. Lithium-ion technologies offer additional benefits that have not been quantified in this calculation. Since lithium-ion batteries are maintenance free, the special charging rooms that lead-acid batteries require for gassing are not needed. This generates space savings, as lithium-ion battery chargers can be installed in the immediate vicinity of the working areas of the trucks. When compared directly with lead-acid batteries, trucks equipped with lithium-ion batteries not only have a higher performance, but performance remains the same over the entire discharging process. In contrast to lead-acid batteries, the user will not notice any performance reduction during discharge. This is reflected in noticeably higher throughput performance. A final argument in favour of lithium-ion batteries is their suitability for rapid and compensation/intermediate charging. This helps to increase the availability of trucks, and make availability more flexible, which in turn has a positive effect on process reliability. Depending on the battery charger that is selected, 50 percent of the battery capacity may be charged in just 30 minutes. Lithium-ion batteries equipped with a Battery Management System communicate with the battery and on each compensation charge, e.g. during the operator’s breakfast break, draw the amount of current appropriate to their charge status. This allows one battery to be used over multiple shifts. The calculation does not take into account the capital value considerations for the lithium-ion batteries. Jungheinrich, for example, offers a warranty of five years or 10,000 operating hours for its lithium-ion batteries. When they are no longer useful in trucks, the batteries have a high residual value and can be transferred easily to other uses. In summary, we can conclude that lithium-ion technology, that is batteries, battery chargers and trucks, from Jungheinrich is superior to lead-acid technology in virtually all areas and represents a viable alternative when the economic considerations are taken into account. The triumphal march of lithium-ion batteries can no longer be stopped, the end of the lead-acid age in the logistics industry is beckoning. Photograph/graphic: Jungheinrich WORLD OF INDUSTRIES – INTRALOGISTICS & DISTRIBUTION 5/2017