The rising world population, scarcity of natural resources and threat of global warming have all contributed to an evolving paradigm shift with regard to mobility and its rising carbon footprint. Today, there are an estimated 800 million motor vehicles on the road worldwide, with this number expected to triple by 2050 . Increasing industrialization and higher per capita incomes could raise global automotive demand even further, exacerbating climate change and severely affecting the sustainability of life.
Many countries are already taking critical measures to innovate on automotive technology, developing mobility solutions that could reduce their dependence on fossil fuels and utilize a cheaper and cleaner energy source instead – electricity. China has, for example, initiated various subsidies and tax incentives to stimulate the development of its “new energy vehicles”. Its goal to pioneer future electric powertrain and battery technologies is also expected to significantly help cut the country’s overall carbon emissions. Many other Asian countries are also readily embracing e-mobility as a panacea to their automotive pollution woes, strongly supporting and promoting sustainable local automotive innovation and development.
E-mobility solutions are becoming increasingly attractive for several reasons. For one, the energy efficiency of an electrically-powered vehicle is almost twice that of one using a combustion engine . In addition, a report from the U.S. Department of Transport indicates that e-mobility is expected to save up to 40% of the carbon emissions of conventional petrol cars over their full life cycle. With more wind farms and solar power plants being initiated to provide an increasing energy grid of clean and sustainable energy, e-mobility innovation can contribute significantly to reducing global carbon emissions and help in protecting the environment.
Over the next few years, e-mobility innovation and prototyping are expected to become more prevalent across the world. Major car manufacturers are already intensifying their research and development in this area, racing to be the first to introduce the latest e-mobility applications. Toyota Motor, for example, plans to introduce its first fully electric car to customers by 2012. Accordingly, the impact on related industries such as power companies and component suppliers in battery technology will also be significant in the light of the shift in demand and requirements.
It is unlikely that rapid structural change will occur in the automotive sector in the near term, as many of the problems surrounding e-mobility adoption have yet to be resolved. The key challenges faced by car manufacturers are typically battery related, among them, the safety aspect of using lithium-ion batteries, a key component of e-mobility drive systems, high battery costs and life span issues, as well as limitations in recharging times.
Global safety standards have also yet to be properly formalized for lithium-ion battery use. Such batteries comprise different combinations of anode and cathode materials, each one with distinct advantages and disadvantages in terms of performance, power levels, cost, and other parameters. As such, each combination has to be adequately covered by testing criteria to determine their risk potential in terms of functional, electrical, chemical and mechanical safety.
A critical success factor for e-mobility is how safe lithium-ion batteries really are. Major car makers are already using lithium-ion packs to increase the range of both electric cars and hybrid vehicles, because of their higher energy density compared to conventional batteries. However, the way lithium-ion batteries perform in a dynamic crash has, to date, been largely undocumented. Without the proper installation or crash-test requirements being established, the failure of these batteries during an accident could undermine the reputations of car and battery makers, and seriously impact the safety of drivers, pedestrians and rescue personnel.
To address such concerns and define the scope of these urgently needed standards, TÜV SÜD successfully conducted the world’s first dynamic crash test of lithium-ion batteries to determine how they perform in crash situations and to identify the ideal structural protocols required to ensure maximum safety.
Using a customized high-precision impactor system and lithium-ion batteries typically used in Mercedes S400 hybrids and BMW 7 series cars, the test was carried out at the TÜV SÜD test ground in Munich Allach to simulate actual crash scenarios and explore the structural parameters of lithium-ion batteries. This helped determine the maximum load and safety levels of such batteries and also identified other potential causes of battery damage during a crash.
To begin with, a lithium-ion battery was packed in a steel case and mounted on a 110-tonne block of concrete. An impactor with various impact bodies and variable weights was then fastened to a TÜV SÜD-patented Electronic Controlled Vehicle (ECV) and driven toward the battery pack. Shortly before impact, the impactor was decoupled from the carrier so that it crashed into the battery in free flight. This allowed the crash test to simulate speeds of up to 55 km/h, weights of up to 500 kg and a resultant energy of almost 60 kJ.
The first test was performed at speeds of 18 to 29 km/h. Although the force of the impact on the battery did not sufficiently cover all possible accident scenarios, it roughly corresponded to the impact of a typical crash. The result was positive - the battery packed in the steel shell withstood the crash, with the deformation caused by the actual dynamic test almost identical to that calculated on the basis of a static test. Crash tests were also performed using batteries packed into materials other than steel. In each case, the same test arrangement resulted in expected differences.
During the tests, an important finding was observed - the lithium-ion battery which had split and leaked in the crash did not immediately ignite or explode. However, battery deformation created an internal circuitry issue which saw constantly increasing temperatures and this caused the battery to catch fire after six hours. Further testing will need to be carried out to obtain conclusive and proven crash-test results which will serve as the basis to develop binding safety standards for lithium-ion batteries.
E-Mobility is only as clean as the power it consumes, which is why the availability of ‘green’ electricity grids is crucial to the success of e-mobility solutions. In many countries, energy production is still largely fossil-fuel driven. Using energy derived from such sources to power e-mobility technology may actually negate any potential environmental benefits and result in higher conversion costs. However, with more renewable energy sources coming online through the harnessing of wind and hydropower for example, car manufacturers can safely expect to effectively reduce the carbon footprint of their e-mobility solutions in the future.
The primary advantages of e-mobility applications over conventional gasoline cars are their lower emissions and higher efficiency. Using e-mobility solutions powered with renewable energies can reduce emissions down to as low as five grams/km with no polluting byproducts. However, the trend towards e-mobility goes beyond simply more environmentally friendly vehicles. With rising petrol prices at the pump and the demand for fast and more efficient cars, even those not necessarily concerned about the environment are attracted to the option of driving cars that are cheaper, lower in maintenance and safer to drive.
There is no doubt that e-mobility is set to change the face of vehicle manufacturing. Over the next few years, demand is expected to increase steadily, making mobility more independent of natural resources and achieving greater sustainability in the process. However, the complete adoption of e-mobility solutions will need to be undertaken systematically, integrating all the elements of a vehicle system, from design, energy generation and distribution, to storage technologies and battery management. In the meantime, car manufacturers will simply continue to innovate on conventional propulsion technologies until the time when e-mobility becomes the status quo.
Assistant Vice President Industry - Automotive TÜV SÜD PSB Pte. Ltd.
