Dreams of ‘Free’ Electric Energy a Long Way Off

Since 2019 the term ‘self-charging hybrid car’ has been touted by most of the top automaker brands.

With the future of connected and autonomous vehicles (CAVs), being electric the very notion that a car can charge itself overcomes the need for charging points. In the future there may also be the possibility of removing the hybrid element involving vehicle charging with a combustion engine, to become totally electric while still have the ability to self-charge.

Removing barriers

If this idea ever happens, and the industry moves away from concept of self-charging hybrids to being completely self-charging or ‘regenerative’, this concept could make EVs more attractive to consumers. ‘Drivers’ would have the freedom to go wherever they want without having to worry about whether they will at any point during their journey run out of juice. It would also negate the need for expensive charging infrastructure and opening up EV ownership to all consumers, especially those without garage or driveways.

Yes, hybrid vehicles can charge themselves. However, by 2035 in the UK these will, like their gasoline and diesel alternatives, be phased out. Meanwhile, Sebastian Gray, assistant manager for Mobility 2030 at KPMG comments: “I think the term ‘self-charging’ can create some confusion. What is referred to by ‘self-charging hybrid’ is in fact a conventional hybrid vehicle. These are cars that charge their battery from (and in some cases take drive from) an internal combustion engine (ICE). Conventional hybrids have been around a long time, with Toyota first launching the Prius in Europe in 2000.”

Embrace self-charging

The next step, therefore, has to embrace self-charging, regenerative technologies that reduce the reliance on, and the need for, expensive charging infrastructure. More to the point, even in a fully autonomous landscape, which is favored by mobility providers because they believe that it will reduce vehicle ownership and congestion on our highways, a layer of flexibility and robustness will be added by having a vehicles that can use its own kinetic energy to charge itself.

Regenerative braking is one technology that is already being used by, for example Volkswagen, to enable hybrid and electric vehicles to use the braking to create energy.  When the vehicles brake, their electric motors turn into a generator, turning the energy produced into electricity. All vehicles create kinetic energy. Regenerative braking is a good concept. However, the ideal situation would be for the regenerative, self-charging process to occur constantly, whether or not a vehicle braking.

Yuan Zhang, associate director for Mobility 2030 at KPMG also points out that there is a technology that is often referred to as being ‘self-charging’, and that is ‘dynamic inductive charging’, or ‘dynamic wireless electric vehicle charging’. Qualcomm Halo WEVC technology is but one example, which was first demonstrated in May 2017.  

After the test, Qualcomm handed it over to Vedecom for further trials for FABRIC, a €9M ($10M) large scale integrated feasibility analysis and development of on-road charging solutions for future electric vehicles project that is co-funded by the European Union’s 7th Framework program. It was implemented by 25 partner organizations from 9 European countries between 2014 and 2017. FABRIC says it aims to address, “the technological feasibility, economic viability and socio-environmental sustainability of dynamic on-road charging of electric vehicles.”

Anyway, Zhang explains what dynamic inductive charging involves: “This typically refers to a system that wirelessly charges a vehicle while it is moving with a wireless induction pad that is built along a stretch of road. It typically requires the car to be a ‘battery electric vehicle’ (BEV) or plug-in hybrid. It’s a great concept – relying on the road to give you power, with no moving parts or maintenance – but runs into some practical roadblocks.”

Regenerative standard

Zhang expects regenerative braking to be the standard in almost all EVs as the key mechanism for extending their range. He reveals: “It’s already included in models such as the Leaf, Tesla Model 3, Hyundai Kona, Mitsubishi Outlander, etc. It’s also the way that most conventional hybrids (e.g. the Prius hybrid) charge their battery without needing to plug in.” However, he says research is bound to continue into dynamic induction charging and dynamic wireless electric vehicle charging. However, he concludes that their practical installation on public roads is very far away.

So, how feasible is it to develop electric cars that can use their own kinetic energy to charge themselves? Gray says this is “unfortunately impossible according to the law of conservation of energy. It isn’t possible to have a car be a 100% efficient system due to mechanical, electro-chemical, aerodynamic and rolling resistance losses, so energy needs to be added to the system somehow in order to keep it going.”

Yes, he explains, some hybrid and electric vehicles do today use some element of self-charging to recover some of the kinetic energy while braking, with regenerative braking but when they do this the vehicles “recover less energy than was put in to get them moving” in the first place.

Ongoing development

Despite this, much work is still going into electric vehicles to extend their range and limit the need for charging infrastructure. This can only be good news for EVs, whether they are connected or going to be fully autonomous, because now is the time to create the future. With the ongoing development of self-charging technologies, the prospects for electric vehicles becoming commonplace on the world’s highways will become increasingly promising.

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