My vision of the hypercar of the future
Filipp Khodakov
Chief technology officer, Leading the team of scientists and engineers, developing breakthrough technologies in electric and ICE engines
New age dictates our dependence on sustainable development, we can not dream of fast cars without thinking of environment, thus, fuel economy (or energy economy I should say) and emissions play an important role in future concepts.
While electric car manufacturers like Tesla, Lucid, Rimac and others showed us incredible potential of full electric vehicles, problems associated with convenient charging infrastructure, or, should I say, lack of it, prevent total EV (electric vehicle) popularization. No matter how beautiful, fast and cool any full-electric hypercar may be - it would remain no more than a toy, at least for the next 5-10 years, as it is impossible to go anywhere on it without fear of running out of juce in the middle of your journey. This psychological phenomenon is known as “charging anxiety”. A term “charging anxiety” appeared with global popularization of EVs with lacking development of charging infrastructure. EV owners all over the world always look at their charge a lot more than ICE car owners look at their fuel level gauge, because consequences of finding yourself out of energy are far greater, as you can not easily top-up your charge in the middle of the road (as you can do with fossil fuel).
Also there is a huge drawback, which marketing teams of all manufacturers try to hide, it is battery degradation which is caused by rapid charging. Any li-ion batteries’ degradation is directly proportional to charging power: the faster (more powerful) the charging, the faster the degradation. Tesla model 3, for example, when charged only on fast chargers and used as a taxy can loose up to 60% of its battery capacity in a year (sourse).
Definately hybrid
Hyper cars of the future will have some form of internal combustion engine just because you can not physically beat that awesome energy density of fossil fuels. Batteries have hit their limit of energy density around 5 years ago, and it is impossible to improve it significantly, because there is no way you can store more potential in the cristal structure of any existing or future material. There is a simple physical limit, and we are very close to it today.
Fossil fuels, on the other hand, are not only very energy-dence, (petrol and diesel are among the most energy-dence substances), but also they use ambient air as an oxidiser, eliminating the need of carrying useless weight around all the time, as oppose to battery-powered vehicles.
Regular fossil-fueled cars, however, have a significant drawback, they are a lot less energy efficient that hybrid vehicles. Everytime that a car decelerates from high speeds, it dissipates huge kinetic energy into heat, everytime a car with huge, powerful engine idles, it uses a lot of energy just to keep this huge engine running, these are examples of easy-fix inefficiencies that can be addressed by switching to hybrid powertrain.?
The right chemistry
Hybrid car can be definitely made more efficient than regular fossil fueled car, but how can we determine the ratio between the power of ICE (internal combustion engine) and EM (electric motor) and what consequences we face when choosing it wrong?
Most manufacturers use the well known Pareto optimal ratio, which is 80/20, where 80% is the maximal power of ICE and, respectively, 20% EM, but now we see that this trend is changing in favor of EM. Chinese manufacturer LI (Leading Ideal) was one of the first proponents of the “hybrid EV” theory, where the ratio is in favout of EM with 60%EM and 40% ICE respective power output. Hybrid EV means that the vehicle is primarily an EV, but in order to eliminate charging anxiety, a vehicle has ICE which is meant to be used as a range extender.?
I think that the ratio should be determined upon which driving style the customer has, and for hypercars, we would assume, the driver wants to be “rewarded” for his “frisky” driving style with the most efficiency on this regime. We want to maximise efficiency under braking (in order to do thet, we need bigger battery charging power capacity), but we also need to minimise weight and for that we need to minimise the weight of the heaviest element of the vehicle, the battery. We don’t care about range, as we have an ICE rande-extender on board, so we care only about maximal power-output of the battery, not the overall capacity.
That means that we can derive form previous reasoning, that we need a battery with most power-density, and with least degradation, that’s it.?
Let’s see then what would be the best option:
(Graphs)
Typical LTO cell will get you 1800 W of power from just 510 grams that is approx 3529 W/kg power density, where typical Li-ion cell can provide 45 W from 47 grams, that is approx 957 W/kg. Li-TI cells are 3.5 times more powerful.
With weight energy density of 47 Wh/kg for LTO and 200 to 300 (Wh/kg) for typical Li-ion sells. LI-ion cells are 4-6 times more energy dense.
Sourse:
领英推荐
If our main goal is maximum power and reliability with minimal weight, then we can see from the information above that the best option is Lithium-titanate.?
“The 2.9 Ah SCiB? cell maintains over 80% of its initial capacity after 40,000 charge/discharge cycles at a tough charge/discharge rate (10C) and high temperature (35°C) conditions.” (https://www.global.toshiba/)?
Regular high-power Lithium-ion cells usually have a cycle life of 1000 cycles to 80% degradation. So it’s 40 to 70 times difference in durability!
LI-TI is the most expensive type of chemistry with energy density 4-6 times lower, and power density 3.5 times higher, however, in luxury segment, consumers don’t really care about the price and with ICE generator on-board, electric range (energy density) is not an issue.
What is the ideal ratio
Electric motors are the more efficient the bigger and more powerful they are. From a certain efficiency threshold, it becomes better to utilize electric transmission, thus the more powerful the drive-train - the better, ironically. At combined power levels of 4000 kW, in terms of energy source, I suggest using 50/50 ratio, and here is why:
We need to maximize the charging power of the battery, to maximize recuperation efficiency under heavy braking, otherwise the vehicle would not be a proper hybrid. We also need to have a powerful enough ICE to provide power generation for sustaining high speeds and if we want to have fun on the track.?
Let us look at the example:
Under braking, the motors will recuperate deceleration energy up to 2000 kW, additional deceleration power will be delivered by brakes in extreme cases; My technology allows to use motors as generators with even more power than in regular motor mode, so the deceleration rate would depend only on battery capacity, and if you have poor deceleration - you will get impressions like these :https://youtu.be/Via70c8rOOY?si=lWIF0RPjafK3h0e0?
In the video mentioned above, bloggers while testing the vehicle talk about how braking performance lacks in it. That is because in BLDC motors (which are used in most EVs and hybrids now) recuperation is very poor, and limited my the strength on magnets in the rotor.
Acceleration will be realized by electric motors, which will utilize combined energy delivery from the battery (2000 kw) and from ICE (2000 kw) through electric transmission.
In proposed above configuration if battery would be from mentioned above LI-Ti cells, it would weigh 708 kg, so the overall weight of the vehicle can be around 2 tons. As there will be engines on all 4 wheels, motor cases can be a part of suspension and overall structure of the vehicle can be unified with the battery to increase rigidity. Battery shape can also be designed in such a way, that it will increase structural rigidity of the vehicle: a shape thick in the middle (between passengers) and on the sides, but thin under passenger seats, for example.
If we make the battery lighter - it will be less powerful, so the vehicle overall will be less efficient as a hybrid, and if we make the battery bigger - the vehicle will be too heavy, it will affect:? acceleration, braking and cornering, parameters crucial for any fast car: Similar philosophy can be applied to ICE, if it would be less powerful - it would not be able to generate enough power to sustain long high speed trips, and it is very hard to make a reliable long-lasting, yet light enough engine with more than 2000 kW of continuous power output. 2 MW for 6 liter ICE is also very hard, but not impossible. We can utilize EGTRS (exhaust gas temperature recuperation system), which boosts the power output of any ICE up to 25% without any additional strain on its components, and we can use single or sequential turbo system for forced induction, instead of twin-turbo systems, which manufacturers usually use when they want to make a versatile engine. In this particular case versatility of an engine is not required, as we can extract power at any RPM, so we can design an ICE for certain RPM and load to perform most efficiently and with the most power output. This is the beauty of electric transmission: it has very similar efficiency with CVT transmission, yet a lot more durable and reliable.
In described above configuration (50/50 power from ICE and battery, 4000 kW total power and 2 ton weight) the resulting vehicle would have power-to-weight ratio of approx 2500 hp per ton, which is a lot higher than all existing hypercars. Current F1 car (2023) has power-to-weight ratio of 1253 hp per ton.
A new phylosophy of future transportation
Typical journey usually is around 5 to 10 (km). In a described above example the battery capacity would be around 33 kWh, which equates to 150-170 km of range. With my technology “charging without a charger”, mentioned in my another article, a person would be able to charge the vehicle anywhere (in the parking of a shopping mall, or office, or wherever). In this case, a person may drive to work every day up to 70 km (which is 7 times the maximum average distance of regular trips), and, charging with regular 16 Ah 230 V connector, add 3.7 kWh of charge (or approx 22 km of range) per hour of charge, would even have no need to charge at home! (After 6 hour charge battery in this case would be almost fully charged from 0, and good to go for 140 km).
During regular driving on public roads with the configuration, described above, almost all power from decelerating would be put back into battery, thus, brakes can be made from exotic expensive materials, with very low maintenance costs, as they would be utilized only in case of emergency, or on the racing track.