Ultra-Lightweight Structures make Electromobility affordable

Scientists at ILK and LZS together with their partner ThyssenKrupp have developed an electric vehicle weighing less than 900 kilograms. Research findings will be presented at the 64th IAA Motor Show in Frankfurt, Germany.

Dresden. The Institute of Lightweight Engineering and Polymer Technology (ILK) at the Technische Universität Dresden with Leichtbau-Zentrum Sachsen GmbH (LZS) and their partner ThyssenKrupp AG have developed an ultra-lightweight vehicle in a joint project named InEco.

The electric-powered vehicle weighs less than 900 kilograms. Using consistent lightweight engineering allows researchers to fully benefit from the advantages offered by the electric drive. The generic lightweight electric vehicle is designed for urban areas, addressing in this way the needs of commuters and short-distance drivers. Within this project vehicle, the scientists have combined sportive driving pleasure with cost-attractive manufacturing methods and environmentally friendly use.

From research to electric vehicle – InEco

InEco stands for ‘Innovation-Electromobility-Composite’ and this is the name of the vehicle on which experts have been carrying out their joint research. Contrary to common practice which normally only focuses on individual parts of a vehicle and substitutes them with more weight efficient ones, the InEco project scientists have targeted the entire vehicle concept. This holistic research approach has led the researchers to an innovative, integrated multi-material design which uniquely defines InEco.

To minimise the production costs of the composite components used, which have been created from carbon fibre reinforced plastics (CFRPs), the InEco project scientists have concentrated their efforts on a level of process development capable of large-series production. The manufacturing methods have been streamlined and automated. The idea has been to build highly integrated designs. Compared with conventional architectures, the new approach has saved multiple manufacturing and joining operations, making the vehicle components cost efficient — despite high-grade raw-materials.

The examination of individual vehicle parts could not be disregarded, though, in spite of this holistic approach. For example, crash behaviour was studied and verified on specially designed assembly demonstrators in Dresden. By using dynamic impact testing, the energy absorption capacity of side skirts was investigated. The traditional steel designs were exchanged for hybrids to create a lighter and, hence, weight-optimised structure featuring the same crash properties.

Steel is making CFRPs compliant

Ultra-lightweight design is the top priority for all system components. The researchers focus, in particular, on hybrid designs composed of steel and CFRPs. The components use ‘the right material at the right place for the right price and at the right ecology’. By adopting the guiding principle that steel makes CFRPs compliant, the high ductility of steel is combined with the highenergy absorption potential of the CFRPs in order to develop extremely lightweight and crashresistant component solutions.

Innovation by integration

The structural components and the drive train of the InEco research vehicle are highly integrated. The single-component floor structure, as an integral component, embodies much functionality leading to weight savings and the reduction of manufacturing steps. Hence, the InEco concept guarantees a marketable execution ready for series production.

The chassis weighs in at only 120 kilograms. With these results, the scientists have opened up a new path in the area of lightweight auto bodies. Together with ThyssenKrupp AG, they have merged the specific material immanent advantages to a new material mix of low weight and good crash behaviour within the composite-steel-hybrid construction.

The InEco vehicle project uses lithium-ion battery technology. The battery containment is positioned in a crash-proof place close to the vehicle’s centroid at the middle of the floor structure, being enclosed by a tunnel. The tunnel has been dimensioned to accommodate as well flat-, round- or block-cells. The battery system possesses a climate-control function which keeps the cells at the correct temperature during driving. In offering a vehicle range of 100 to 150 kilometres, the battery concept is capable of providing sufficient energy for this target range.

A permanently excited synchronous electric motor connected to a differential will accelerate the vehicle from 0 to 100 kilometres per hour in only 7.4 seconds.

Besides its technological breakthroughs, its aesthetic appearance will clinch the successful public acceptance of the electric vehicle. With InEco, the scientists have committed themselves to move away from conventional electric vehicle concepts to new sportive and ecological alternatives.

Premiere presentation at the 64th IAA Motor Show

Research results will be presented at the 64th IAA Motor Show in Frankfurt am Main, Germany, from 15th to 25th September (Hall 4.0 / Stand D24). Especially built for the IAA Motor Show, the InEco project scientists will have a 1:4 scaled design model to provide the visitors with an impressive idea of this novel electric vehicle. Moreover, the team will show a composite-battery tunnel, pressed in series production technology, which was developed by the project partners.

Other exhibits will be an innovative, ultra-lightweight axle assembly with CFRP-suspension and a newly developed hybrid side skirt as a composite-steel-hybrid design with an extremely high energy absorption capacity.

This project is part of an overall plan named ALIEN funded by the European Regional Development Fund (ERDF) of the European Union and by the Free State of Saxony.

SOURCE: LZS

Technical specifications:

Engine & performance:

Type: Synchron-Elektromotor

Top speed: 160 km/h

0-100 km/h: 7.5 s

Dimensions:

Length: 4200 mm

Width:  1900 mm

Height: 1440 mm

Weight: < 900 kg