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BATTERIES WILL PREVAIL IN THE RACE TOWARDS GREEN MOBILITY

Batteries are controversially discussed. Nevertheless, most manufacturers and legislators rely on battery electric vehicles – the right decision.

  • Batteries have significant advantages over all alternatives
  • Traditional fuels such as diesel and petrol make neither economic nor ecological sense
  • Hybrids are nothing more than a bridge technology
  • Fuel cells have a low Well-to-Wheel (W2W) efficiency compared to batteries and do not suit a mass market

Earlier this year, a much-discussed study by the Munich-based economic research institute Ifo criticized electric cars for their ecological footprint. The study claimed that electric vehicles produce more CO2 than diesel vehicles. However, the study’s authors found themselves to be quite isolated in their opinion. Nevertheless, it has triggered a great discussion about the sensibleness of batteries, especially in comparison to other alternatives. Various publications, such as the notorious and meanwhile refuted “Sweden Study”, spread the rumor of the environmentally harmful battery with up to 17t CO2 ecological footprint. Apart from the environmental aspect, which has just been largely alleviated by the Fraunhofer Institute for Systems and Innovation Research ISI, the question of economic efficiency naturally also arises.

In the following article, we will examine in detail why batteries are the future of mobility and play a key role for renewable energies.

Classic combustion engines make neither ecological nor economic sense

The classic powertrain technologies – petrol (gasoline) and diesel engines – have served us very well for over a century. But now, in the 21st century, they lost their central role in energy production, both in mobility and as generators. Jumps in efficiency are no longer possible, which is why the electric motor, in combination with batteries, is already outperforming the combustion engine in many respects.

A combustion engine is highly complex and contains around 2,500 different components that must be developed, manufactured and assembled. In contrast, an electric motor consists of only about 250 parts. Furthermore, there are countless wear parts and necessary complex gearboxes. It is not without reason that after-sales departments and workshops fear a significant revenue decline as consequence of the transition towards e-mobility. If a vehicle can recuperate (energy recovery), the brakes, for example, experience less wear. One of many reasons why workshop visits and required maintenance will decrease overall. In addition, fewer components simply lead to lower maintenance costs. Volkswagen is talking about a decrease of 20-30% of after-sale service costs. Battery-electric vehicles (BEV) are significantly cheaper in operation, therefore, the evaluation must be based on a cost analysis that includes not only the acquisition costs but also the operating costs. Following this approach, the advantages of BEVs become evident.

Not only since the emissions scandal, the combustion engine has been under considerable criticism in terms of air pollution. The combustion process in car engines produces harmful gases and particulate matter from petrol or diesel. Petrol engines emit more CO2 and diesel engines additionally cause particularly high levels of soot particles (particulate matter) and nitrogen oxides. This has direct (urban smog) and indirect (climate change) consequences.

Air pollution from cars is already on a high level that driving bans have been enforced or are being discussed in various large cities. Especially with regard to local emissions, battery electric vehicles have an unbeatable advantage: no emissions during operation.

When talking about the ecological footprint of batteries, there are two main aspects that need to be considered: battery production and energy source. The extraction of raw materials and the production of battery cells and modules account for the majority of emissions. Increased efficiency in terms of production and material input helps not only to reduce emissions, but also costs. Furthermore, manufacturers are increasingly focusing on climate-neutral cell production. Trends such as these will continuously reduce the ecological suitcase that batteries already carry around with them even before they are put into operation.

The key driver for the question when an electric car turns more ecological than a classic combustion engine is the electricity mix. The calculations on the ecological break-even point of battery electric vehicles vary extremely, depending on assumptions and included parameters. An analysis by the magazine Edison of the Handelsblatt, assuming production standards and the German electricity mix of 2017, has calculated a climate advantage of BEVs over diesel and petrol from 50,000 or 40,000 km respectively (battery guarantees are between 160,000 and 200,000 km). It can be assumed that this will shift sharply in favor of the BEV in the course of the energy transition.

Hybrids are not more than a bridge technology

A frequently cited argument against BEVs is the alleged limited range or long charging process. An obvious solution, which is also offered by almost all manufacturers, is to combine the battery with a combustion engine. Hybrids thus combine all the positive and negative aspects of both technologies. The hybrid offers locally emission-free driving on short distances. The combustion engine is used on longer routes. So far so logical. However, this also means that all the advantages are counterbalanced by the combined disadvantages. Every hybrid is in sum more complex as both technologies have to be completely integrated. In addition, drivers never enjoy the power and torque of a pure electric motor – likewise the roaring of a V8 engine is history. Clearly, hybrids are only a bridge technology on the way to a pure electric car. Whether it is sensible to carry around a complete alternative technology every day, seems questionable for an average journey of only 39 km. The analogy with a horse trailer for the first combustion engine cars, with a spare horse inside, should the fuel run out once seems fitting.

Efficiency of the fuel cell only 30 percent of the energy used

Li-Ion Cell vs. Fuel CellPraised as the great alternative to battery electric vehicles, the fuel cell is currently struggling to leave its niche. A hydrogen vehicle is nothing more than an electric vehicle, with the subtle difference that the fuel cell converts fuel into electricity, while a battery stores energy in chemical form. In a so-called “cold combustion”, a continuously supplied fuel (e.g. hydrogen from natural gas) reacts with an oxidizing agent (e.g. oxygen from air). This generates electrical and thermal energy. The sole outcome of this reaction is water. At first sight, this obviously has significant advantages – you can refuel as usual. This would mean that you could also continue to use the network of gas stations, it would go fast, and the range would not be an issue anymore.

Well, that is as correct as it is wrong. Current fuel pumps can by no means be used for hydrogen, which means that a completely new infrastructure must be set up – you could also build a network of fast-chargers that now charge vehicles in less than half an hour. But this is also misleading, because BEVs hardly ever need petrol stations in the conventional sense. Apart from long-distance connections, batteries are recharged in normal day-to-day business – at work, shopping or parking at night. In fact, the topic “refueling” should be considered another huge advantage of BEVs.

Well-to-Wheel EfficiencyIn addition, hydrogen can only be stored in liquid form (energy-intensive to produce) or in gaseous form under high pressure. The efficiency (W2W) of BEVs is 77 percent. Fuel cells, on the other hand, only achieve an efficiency of 30 percent of the energy used – so the truth of the matter is, for the operation of a fuel cell, we would have to build at least twice as many wind turbines or solar plants as for a BEV in order to generate the “green” electricity required.

Apart from these theoretical arguments, there is a very practical problem: so far, no manufacturer has succeeded in producing suitable fuel cells for mass production. Total fuel cell vehicles sales were around 17,000 in 2018 – Tesla alone sold 14 times more vehicles in the same timeframe. Overall, the fuel cell technology is not even close to be fully developed and will take years to be deployed successfully on a larger scale. The fuel cell is currently regarded as a high-priced niche in the automotive market, which will fade away as soon as the battery meets all market requirements. However, it could be used for certain applications. Volkswagen AG also came to this conclusion in its article on the subject of hydrogen or batteries.

Li-Ion batteries are the future of mobility

One thing is for sure: the electric car is unstoppable, because it fits perfectly into the future world of decentralized energy supply and modern mobility concepts, the same way as it reflects the digitalization in economy and society. The advantages of the electric drive are too striking. Electric cars have a great advantage over combustion engines. They have the potential to reduce their CO2 footprint substantially more than vehicles powered by fossil fuels ever could. Thus, they are the best answer to one of the greatest challenges of our time, climate change.

Apart from rational arguments, hardly anyone who has ever driven a BEV will be able to complain about the driving experience – incredible acceleration courtesy of instant torque delivery, excellent handling and responsiveness due to the low center of gravity.

  • About TWAICE

    TWAICE supports enterprises across industries with predictive battery analytics software based on digital twins. We empower our customers to develop and use battery systems more efficiently and sustainably while making them more reliable and durable. Precise predictions of battery conditions and aging significantly optimize battery development and use. Exact determination of current condition also enables certification of batteries for reuse and 2nd life.
    TWAICE was founded in 2018 as a spin-off from Technical University of Munich and is headquartered in Munich. The client base covers a vast array of industries ranging from e-scooters over automotive to stationary energy storage.
    www.twaice.com

Author: TWAICE
Published: 13th September 2019
Location: Munich