Electric Cars – Tell me again why we are using batteries?

I must be missing something with electric cars because I do not understand why we are using batteries for the electricity source.

Let me explain the situation.

Batteries are a way to store electricity for an extended period of time.

But why exactly do we need to store electricity for an extended period of time?

When the car is moving, the energy is “stored” in the form of momentum.

At speeds up to around 60mph the amount of power required to keep the car moving is pretty minimal. For example, a typical family saloon only needs around 16hp to maintain a 60mph. Source: http://www.precisionautoresearch.com/rdp/RDP_Samples/Aero-Forces.xls

I suppose we could haul a huge battery around with us to us to get the 16bhp but why dont we just use an ic instead? Much cheaper and much lighter and needs much less of the worlds resources to build and maintain.

The big energy requirements & changes in normal driving come from acceleration and braking acceleration. Acceleration and braking change huge amounts of energy from one form to another over very short periods of time.

In its current form, the 911 hybrid is about 230 pounds heavier than the 911 GT3 RSRs run by the Flying Lizards team in the American Le Mans Series GT class. At its Nurburgring debut, the hybrid didn’t have the outright speed of the conventional 911s, but it spent more of its time on the track thanks to its ability to achieve 25 percent better fuel efficiency. The use of so much regenerative braking, thanks to the flywheel’s ability to absorb power quickly, also reduced brake wear. The brake pads on the hybrid only had to be changed once in the 24-hour race, compared to 2-3 changes for the regular version. The hybrid’s on-demand all-wheel-drive should also give it a handling advantage in wet conditions.

Again, something that is completely unsuitable for a battery. Again, batteries are designed to store energy for extended periods of time take time to recharge/deploy their energy.

To repeat, a battery is completely unsuitable for an electric car. using a battery in an electric car is like using a hammer to iron your clothes. I suppose you could do it and if you spent enough money developing the hammer I expect it will do the job but why bother when you can use an iron.

Okay, so a battery is completely unsuitable for electric cars, it is the wrong tool for the job but is there a better solution?

Yes.

Flywheel based hybrid. Flywheel based electric generators can store huge amounts of energy and they can be charged and discharged in the time it takes to accelerate or brake a car.

Flywheels are perfect for electric cars. For acceleration and braking events the energy is the flywheel can be used. Braking can be used to charge the system and the stored power can be used to accelerate the car again. The two biggest failings of battery technology are the two things that the flywheel does best.

The two things that cause by far the biggest toll on fuel economy is exactly where the flywheel can bring the biggest benefits.

A battery of course can maintain speed but that is not the aspect of driving that uses the most energy, not even close. Batteries are a solution to a problem which we dont need to solve.

Industrial drives giant GKN and bus operator Go-Ahead have agreed a deal that will see electric flywheel systems, developed for F1 racing, retrofitted to 500 buses over the next two years.

At the moment we need to tackle the low hanging fruit, the things that will lead to the biggest increases in fuel economy.

Technology as it stands today would allow for an electric car with 70% improved fuel economy with a price slightly higher than a normal car in a car that weighs about the same as a car does today. Flywheel electric technology allows this to be a reality

So why do we not see cars equipped with flywheel hybrid technology?

On the road they are non existent, in motorsport and public transport the technology is making in roads

https://en.wikipedia.org/wiki/Kinetic_energy_recovery_system

Construction, service costs and service life, not to mention that big gains that can be expected with regards to speed of charge, amount of braking they can exert and the amount of power and the speed they discharge, I cant help thinking flywheel technology has more potential and will develop faster.

The major problem I see with flywheel systems is that cars will be 50% + more efficient with no corresponding increase in service costs or purchasing costs. A 50% reduction in the expenses of the average motorist will cause issues for fuel companies and governments alike.


This page was last modified Dec 14, 2017 @ 7:03 pm

Richard @ StrikeEngine

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