D he traction battery is not only the most important component in an electric car - it is also the most controversial. Expensive, heavy and produced with a high consumption of energy and raw materials, with a limited lifespan and difficult to dismantle again into its components. The latter problem in particular is currently worrying the industry.
It seems certain for the time being that lithium-ion batteries will primarily be used in e-cars in the future. If e-mobility develops as planned by some manufacturers - VW alone expects, for example, one million e-cars to be produced in 2025 - the issue of battery recycling on an industrial scale must be resolved in the very near future.
Thermal recycling is harmful to the environment
Many recycling concepts for car batteries rely on thermal recycling. To put it simply: the batteries are melted down at a high temperature and individual components such as cobalt, nickel and copper are recovered from the melt. The process has a catch: it's very inefficient. The Lower Saxony-based company Duesenfeld, where an alternative, mechanical recycling concept is used, does the math: This 'pyrometallurgical recycling' causes higher CO2 emissions when melting down the components than when producing a new battery .
Under such conditions, the so-called CO2 footprint for electric cars is not particularly promising: Only recently, VW had calculated that the production of the relatively small traction battery of a VW with 36 kWhE-Golf is responsible for 57 percent of its total CO2 emissions. Further problems with 'meltdown recycling': Highly poisonous gases are produced, as in a hazardous waste incineration plant, which have to be filtered out at great expense. In addition, according to Duesenberg, only cobalt, nickel and copper can be recovered. The rest of the melted down materials will be disposed of in abandoned mine shafts.
A major problem with recycling Li-Ion batteries is their fire hazard. This is why special safety standards also apply to the transport of such batteries, since - if ignited by a short circuit - they can no longer be extinguished with conventional means. The patented trick that Duesenberg uses consists of shredding the old batteries.
First, the large battery packs are dismantled by hand and the housings, covers and other installed components are sorted and sorted. The batteries are first completely discharged, and the energy obtained is fed into the recycling process. The individual battery packs then end up in a shredder. In order to prevent self-ignition due to short circuits during shredding, the batteries are dismantled under negative pressure and with the addition of nitrogen.
During this process, the electrolyte of the batteries is then recovered: It is evaporated from the shredded mass and condensed again. What remains is a dry granulate, from which the individual components are separated using conventional methods - for example using sieves and magnets.
Over 90 percent recycling rate
According to its own information, Duesenfeld can With this technology, up to 96 percent of the battery components can be separated from one another and recovered, among other things, the metals lithium, cobalt, nickel and manganese in a purity that enables use in the new production of lithium-ion batteries. We come full circle.
In addition to the pilot plant in Wendeburg near Braunschweig, Duesenfeld relies on decentralized recycling. AtShredder systems are to be used at local collection points, the technology of which fits into a standard sea container. In this way, the granulate to be recycled should be produced directly on site, which can then be safely transported and reprocessed in a central facility.