From the STROMbegleitung report: operating points of a BEV in simulated ride through the CADC highway cycle applied to the efficiency map of an electrical machine. The dashed line on the operating map show rated torque; the solid line shows peak torque. Click to enlarge.

Trend analysis. Within the study, the DLR scientists developed a database to record all electric passenger vehicles, which they analyzed down to the component level—including series vehicles already in production, prototypes, show cars and research vehicles. They counted more than 500 electric passenger vehicles of all those types worldwide in the period from 2000 to 2013.

A total of 87 new BEV and PHEV production cars were presented worldwide between 2006-2013.

Number of series-production electric vehicles by OEM, 2000-2013. Click to enlarge.

The focus was in particular on electrical machinery, power electronics and various technologies for traction batteries. The study found that activities of international car manufacturers in the field of electrified vehicle concepts (XEV) worldwide increased significantly for the first time from 2006 and especially from 2009 onwards.

However, from 2012, the study found an annual decline in newly introduced vehicles. Non-plug-in hybrid electric vehicles (HEVs) showed a fairly constant number in the analysis; plug-in hybrids (PHEVs) accounted for the largest share of new concept vehicles in 2013.

Annual number of internationally presented electrified vehicles. Click to enlarge.

The study also found that increasing vehicle mass is correlated with a decreasing degree of electrification. Full battery-electric vehicles are mainly found in vehicles under 1000 kg (2200 lbs); the proportion of HEVs increases significantly with heavier vehicles. The largest share of PHEVs were found between a vehicle curb weight of 1500 kg (3,300 lbs) and 2000 kg (4400 lbs).

Degree of electrification by vehicle manufacturers. Click to enlarge.

The analysts also found nearly 52,000 publications and 82,000 patents in the field of hybrid and electric vehicles over a period of 10 years.

At the moment, the automobile industry in Japan and the United States is pioneering the development of marketable vehicle models; they also produce the highest-selling models on the market. 210,000 vehicles with an external capacity to charge the battery (plug-in hybrids and battery-powered electric vehicles) were sold worldwide in 2013—roughly half of them in the United States, which is currently the largest market.

Production of electric vehicles by country. Click to enlarge.

The study indicates that Germany is lagging behind in the research and development of key technologies, especially in the field of power electronics. Here, Japanese companies in particular are driving technological development.

Power electronics are crucial to electric cars; these components control and direct the flow of energy within the vehicle, and are therefore important elements in any further optimisation of the powertrain. This is why enhanced research into components and materials used in power electronics needs more support here in Germany.

—Matthias Klötzke, study project coordinator

Klötzke adds that Germany occupies a strong position in terms of assembly and packaging technology as well as system integration, noting that an additional characteristic feature of the electromobility sector in Germany is the close cooperation between research institutions, manufacturers and medium-sized enterprises. This area should also receive additional support. An analysis of ongoing and announced support programs indicates that Germany already shows the highest levels of investment in research and development within the electromobility sector in Europe.

Rare earth elements and lithium—raw material shortages predicted. Many electric vehicles use permanent magnets based on rare earth elements. These rare magnets exhibit a high energy density and are lighter than magnets made of other materials. The availability of rare earth elements varies greatly; while some are available on the global market from various sources, others are highly dependent on just a few source countries, China in particular.

To expand electromobility, we need to consider alternative motor designs and recycling methods for particularly scarce raw materials, and we have to search for alternative materials.

Lithium-ion batteries are currently used in approximately 80% of electric vehicles, and therefore represent the dominant technology by far. Batteries installed in electric vehicles will continue to use this technology in future; this creates a situation quite similar to that of rare earth elements.

Demand for lithium is reaching a critical level in all scenarios of electromobility considered in the study. Hence, the researchers anticipate a rise in costs and greater levels of pollution in mining operations designed to extract the metal. They recommend continuing the efforts to develop recycling methods for lithium, expanding their application and introducing support programs to conduct research into alternative battery technologies and energy sources.

Resources

• Begleitforschung zu Technologien, Perspektiven und Ökobilanzen der Elektromobilität (German only)