Ecofriendly recycling of lithium-ion batteries

Duesenfeld uses a patented method that combines mechanical, thermodynamic and hydrometallurgical processes. This method delivers exceptional material recovery rates despite needing very little energy input. This is only possible because it does not use techniques which are commonly used in battery recycling like smelting, pyrolysis or heating.

Duesenfeld operates its own process that recycles not only the usual metals, but also graphite, electrolyte and lithium. Material recycling means that instead of being consigned to use in roadworks and other construction, all metals have high recovery rates and can enjoy a second life in the form of high-quality secondary raw materials, even making the grade for use in batteries. Producing secondary raw materials using the Duesenfeld recycling process saves 8.1 tonnes of CO2 per tonne of recycled batteries relative to primary extraction of raw materials1)2). Compared with conventional smelting processes, the Duesenfeld method saves 4.8 tonnes of CO2 per tonne of recycled batteries1)3).

CO2 saving by comparison
CO2 saving by comparison1) 2) 3) 4)

With lithium-ion batteries, the Duesenfeld method achieves a material recovery rate that is almost twice that achieved with conventional recycling methods. Supplemented by hydrometallurgical processes, a recycling rate of almost 100% is possible. The mechanical recycling process can be performed in both stationary and mobile configurations at collection points in 40-foot containers. End-of-life batteries are usually classified as hazardous goods and carried in battery transport containers. In situ mechanical processing separates the electrolyte from the other materials, and there is no need for a special battery transport container for the resultant products. These intermediate products are transported in standard containers, which means that the average truck can carry seven times as many. This reduction in hazardous goods transport eliminates most of the costs for the entire battery recycling process.

Material recovery with the Duesenfeld recycling method
Material recovery with the Duesenfeld recycling method

Our primary aim is to recycle as much of the material in a battery as possible. In its mechanical recycling process, Duesenfeld can achieve a material recycling rate of 72%, while treating the black mass via the Duesenfeld hydrometallurgical process increases the material recycling rate to 91%. Only the separator film and components of the electrolyte with high boiling points are currently unable to be recovered. With these rates, Duesenfeld outperforms the current requirements of the EU's 2006/66/EC Battery Directive by some margin.

Comparison of material recycling rates at battery cell level without battery housing, fas-tening systems, screw fittings, wiring or electronics
Comparison of material recycling rates at battery cell level without battery housing, fastening systems, screw fittings, wiring or electronics

Innovative process chain for recycling lithium-ion batteries

The innovative Duesenfeld process chain has been developed specifically for lithium-ion batteries and is protected by an extensive range of patents. Duesenfeld's unique combination of mechanical treatment and hydrometallurgical processes and the fact that it does not employ high-temperature processes allow battery materials to be recycled to an impressive extent. This makes Duesenfeld the leader in lithium-ion battery recycling technology.

Mechanical preparation

The mechanical preparation of lithium-ion batteries is a challenging task due to the combustible electrolyte and hazardous ingredients. To ensure safe preparation, Duesenfeld has developed and patented a method that eliminates the risks specific to the process.

Following discharging and disassembly, the batteries are crushed in an inert gas atmosphere, and the solvent in the electrolyte is recovered from the crushed material by means of vacuum distillation. A low process temperature prevents the formation of toxic gases. The separated solvent is sent to the chemical industry for further preparation.

The dried crushed material is separated into different material fractions on the basis of physical characteristics such as particle size, density as well as magnetic and electrical properties; these then undergo further metallurgical processing. The iron, copper and aluminium fractions are sent for standard recycling. Duesenfeld has developed a hydrometallurgical method for processing the black mass, which contains the electrode-active materials and the conducting salt. This patented method recovers cobalt, lithium, nickel, manganese and graphite from the black mass.

Recovered electrolyte in the collection container
Recovered electrolyte in the collection container

Hydrometallurgy

In most industrial hydrometallurgical processes currently employed for processing the black mass, only cobalt and nickel are recovered. Lithium, manganese and graphite are lost in these processes and so removed from the material cycle. Duesenfeld has developed and patented its own procedure that enables complete cycle management through the production of battery-grade raw materials for the electrode-active materials.

Recovered graphite
Recovered graphite

The fluoride-containing salt represents a particular challenge in the hydrometallurgical processing of the black mass because it can cause the formation of hydrofluoric acid during wet chemical processing. In a patented, specific pre-treatment step, Duesenfeld completely removes the fluoride prior to leaching, which reliably prevents the formation of hydrofluoric acid. Once the fluoride has been removed, the metals are leached and, as a result, separated from the graphite, which is then sent for material recycling. Lithium, cobalt, nickel and manganese are separated from each other in various extraction methods, cleaned and recovered in the form of salts. The salts act as a base material for the production of new cathode-active materials.


1) Screening LCA, Institute of Machine Tools and Production Technology (iWF), Technical University of Braunschweig, LCA Duesenfeld Process, Professor Christoph Herrmann

2) Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., and Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. The International Journal of Life Cycle Assessment, [online] 21(9), pp.1218–1230. Available at: http://link.springer.com/10.1007/s11367-016-1087-8, Version: Ecoinvent 3.6 cut-off

3) Öko-Institut e.V. Ökobilanz LibRi, 2011, Entwicklung eines realisierbaren Recyclingkonzepts für die Hochleistungsbatterien zukünftiger Elektrofahrzeuge – LiBRi https://www.oeko.de/uploads/oeko/oekodoc/1499/2011-068-de.pdf

4) Basis: To ensure the comparability of the findings, the calculations were performed using 1) the same assumptions as for the calculation 3), including lithium recovery and battery housing recycling. Generic battery composition as per the LCA Umbrella group from the LiBRi/LithoRec projects. Both recycling procedures have been calculated without Carbon footprint (principle of prime responsibility) from primary raw material recover.