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ELECTRIC CARS | How They Work

Feb 27, 2020
- Electric

cars

are taking over the world! They're getting nines in the quarter mile! Oh Lord! But how do

they

work

? The

electric

car may seem like a relatively new fad arriving in the automotive world. But

they

are actually much bigger than you think! In 1834, Professor Sibrandus Stratingh of Groningen, Netherlands, and his assistant Christopher Becker created a small-scale

electric

car, powered by non-rechargeable primary cells. William Morrison of Desmoines, Iowa, built the first successful electric automobile in the United States in 1891. And by 1897, most New York taxis were electric! Crazy! Before we delve into how electric

cars

work

, we need to understand how a battery works.
electric cars how they work
You cannot store electricity, but you can store electrical energy in the chemicals within a battery. There are three main components of a battery. Two terminals, or nodes, made of different chemicals, usually metals, the anode and the cathode. And then there is the electrolyte, which separates these terminals. The electrolyte is there to bring the different chemicals of the anode and cathode into contact with each other so that the chemical potential can be balanced. (Comic overlay of the words of the term) During the discharge of electricity, the chemical in the anode releases electrons to the negative terminal into ions in the electrolyte.
electric cars how they work

More Interesting Facts About,

electric cars how they work...

Meanwhile, at the positive terminal, the cathode excludes electrons, completing the circuit for electron flow. Convert stored chemical energy into useful electrical energy. That's what generates an electric current! It took a while before we improved battery technology enough to be able to power a vehicle to travel practical distances. But guess that? We've got them! (applause) The batteries in most hybrids and all-electric cars, I'm looking at you, Elon, they look like this. This metal box contains a long spiral formed by three thin sheets pressed together. Inside the box, these sheets are immersed in an organic solvent, often ether, which acts as an electrolyte.
electric cars how they work
The separator is a very thin microperforated sheet of plastic. The positive electrode is made of lithium cobalt oxide, the negative electrode is made of carbon. When the battery is charged, lithium ions move through the electrolyte, from the positive electrode to the negative electrode, and adhere to the carbon. During discharge, lithium ions return from carbon to lithium cobalt oxide. It's the same principle as any other battery, but because these batteries can store both electrical energy and chemical energy, lithium-ion batteries are what help electric cars make the leap from novelty to reality. The best thing about lithium ion batteries is that they can be recharged again and again and again and again.
electric cars how they work
The lithium-ion batteries in the Tesla battery pack are actually very similar to the rechargeable batteries you'll find in stores. They are also commonly used in vaporizers. (speeding car) (exhaling smoke) Each cell contains 4.2 volts and approximately 30 amps. What does that mean? Electricity flows like water, so let's think about where we store water, in a tank! There is a reservoir here behind a dam. The water back here is like the voltage of a battery. It's like a stored charge. If we let some water out of the dam, we can measure the flow. In a battery, this current is measured in amperes.
In a battery, amperes measure capacity. That's how fast energy can flow. If I put more water in the dam, the flow may still be limited. Therefore, higher voltage may be limited by amperage. Plus, if we increase the flow without increasing the load, we run out of juice before it has any use for us! In a battery cell, amps measure capacity, basically how well current can flow. Connecting cells together can increase voltage, stored energy, amperage, current flow, or both! If I connect a series of batteries, I double the voltage while maintaining the same nominal capacity. If I connect a battery in parallel, I double the amperage while maintaining the same nominal voltage. 7,104 cells in the Tesla Model S battery are connected in a combination of parallel and series, over 16 modules to increase both voltage and amperage to 1,500 amps and 400 volts!
That's a lot of juice! But how do they move? In the early 19th century, everyone was someone who played with electricity and the resulting currents. So it wasn't long before people realized that wrapping wires and sending currents through them generated magnetic fields. If you've ever tried to touch the north ends of two magnets (buzzing sound), you know that there is a tangible physical force that magnetic fields can generate. Electric motors use this force to drive movement. The Tesla Model S uses a motor first invented by Nikola Tesla about 100 years ago, the induction motor. The motor consists of two parts, the rotor and the stator.
The rotor is a series of conducting bars, short-circuited by terminal rings. A three-phase AC pulse is sent to the stator. This alternating current produces a rotating four-pull magnetic field, or RMF. The electricity passing through the stator induces current in the metal bars of the rotor. Just as magnets can attract or repel each other to cause motion, the rotating field of the stator causes motion in the now charged rotor. In an induction motor, the rotor is always just behind the RMF. The speed of the rotor is determined by the frequency of the alternating current passing through the stator.
When you step on the accelerator, you are actually increasing the frequency of the current. An inverter switches the direct current from the batteries to alternating current to drive the motor. It is located right next to the motor and has all the guts to determine the frequency of the current, which determines the speed of the rotor and the amplitude of the current, which affects the power output of the rotor. That's determined by a variable frequency drive attached to all of this, right here. The only points of contact are the bars that hold the rotor in place. There is no other contact between the rotor and the stator.
That's why it's hard for them to wear out. And unlike a conventional motor, whose usable torque is found only within a limited rev range, typically below 8,000 RPM, the Tesla motor can effectively produce force in a rev range up to 18,000 RPM. Therefore, there is no need for shifters or torque converters. Additionally, unlike conventional motors that convert the up-and-down or side-to-side motion of pistons into rotational motion, the induction motor produces exclusively rotational force, meaning that almost anything that can be rotated in forward movement when the wheels hit the ground. path. Traditional internal combustion engines can weigh up to 600 pounds.
A Tesla Model S motor can generate 362 horsepower and only weighs about 70 pounds. But you have to remember that they get all that power for those horses, from a 1200 pound battery. (car skids) Even with that huge battery, the Tesla Model S has 443 pound-feet of torque and 416 horsepower that gets it to 60 miles per hour in 4.2 seconds—for a sedan! Tesla says his biggest concern with dumping all that energy and spinning the rotors at 18,000 RPM is heat. Therefore, most components, including the motor, variable frequency drive and battery, are liquid cooled so that they do not overheat. Oh, and here's the other thing about Teslas.
The induction motor, when not producing motion at the wheels, can be turned by the wheels, making it something like the alternator in your car, recharging the lithium-ion battery! So more motors means yes, you get more power through the wheels, but it also means more charge goes back into the battery when you're rolling and braking. It's responsible! But manufacturing these cars and charging them will also cause emissions. There are no completely ecological cars. Well, you're right. There is no such thing as a truly carbon neutral car. But even taking into account the carbon generated by manufacturing the cars, electric cars have a significantly lower carbon footprint than gasoline-powered cars.
And the process is becoming more efficient. If you want to help Donut create more great content, visit Brilliant.org! They sponsored this episode. Heck, not only sponsored, but the information on Brilliant really helped us write this one! I went through this episode reviewing electricity and magnetism practice problems. How do you think I learned to do this? (Buzzing, laughing) And then, I looked up the user-generated explanations to better understand how this all works. In reality, solving the problems makes the concepts much clearer. More than just reading about them. The community wants to help you, challenge you and inspire you.
What better way to get excited about math and science! Go to Brilliant.org slash science garage and sign up for free. Additionally, the first 200 people to access the link will get a 20% discount on their annual premium subscription. See you there! Bright! Press this button to subscribe to Donut so you'll never miss an episode of Science Garage. Follow me on Instagram @Bidsbarto, follow Donut @DonutMedia. Get yourself some t-shirts, we have lots of new things at shop.donut.media. We talked about vaping, check out this updated on the WRX. Also, check out this new car show about the Tesla Model Three.
Don't tell my wife I'm still tongue-tied. Tingling.

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