Motor Mouth: The battery revolution will make electric cars practical

On the upcoming Wednesday, November 24, the latest round table of Driving into the Future will discuss what the future of Canadian battery production might look like. Whether you are an optimist-you really believe that all cars will be electric by 2035-or you think we will not reach that ambitious goal, battery-powered cars are an important part of our future. If Canada wants to be a part of this electric revolution, we need to find a way to become the leading manufacturer of automotive power systems in the future. To see what the future looks like, watch the latest battery manufacturing roundtable for us in Canada this Wednesday at 11:00 am Eastern Time.
Forget about solid-state batteries. The same goes for all the hype about silicon anodes. Even the vaunted aluminum-air battery that cannot be charged at home cannot shake the world of electric vehicles.
What is a structural battery? Well, this is a good question. Fortunately for me, who doesn’t want to pretend that I may not have engineering expertise, the answer is simple. Current electric cars are powered by batteries installed in the car. Oh, we have found a new way to hide their quality, which is to build all these lithium-ion batteries into the floor of the chassis, creating a “skateboard” platform that is now synonymous with EV design. But they are still separate from the car. An add-on, if you will.
Structural batteries subvert this paradigm by making the entire chassis made of battery cells. In a seemingly dreamlike future, not only the load-bearing floor will be-rather than contain-batteries, but certain parts of the body-A-pillars, roofs, and even, as a research institution has shown, it is possible , The air filter pressurized room-not only equipped with batteries, but actually constituted by batteries. In the words of the great Marshall McLuhan, a car is a battery.
Well, although modern lithium-ion batteries look high-tech, they are heavy. The energy density of lithium ion is far less than that of gasoline, so to achieve the same range as fossil fuel vehicles, the batteries in modern EVs are very large. Very big.
More importantly, they are heavy. Such as heavy in “wide load”. The basic formula currently used to calculate the energy density of a battery is that every kilogram of lithium ion can generate about 250 watt-hours of electricity. Or in the abbreviation world, engineers prefer, 250 Wh/kg.
Do a little math, a 100 kWh battery is like a Tesla plugged into a Model S battery, which means that wherever you go, you will drag about 400 kg of battery. This is the best and most efficient application. For us laymen, it may be more accurate to estimate that a 100 kWh battery weighs about 1,000 pounds. Such as half a ton.
Now imagine something like the new Hummer SUT, which claims to have an onboard power of up to 213 kWh. Even if the general finds some breakthroughs in efficiency, the top Hummer will still drag about a ton of batteries. Yes, it will drive farther, but because of all these additional advantages, the increase in range is not commensurate with the doubling of the battery. Of course, its truck must have a more powerful — that is, less efficient — engine to match. The performance of lighter, shorter range alternatives. As every automotive engineer (whether for speed or fuel economy) will tell you, weight is the enemy.
This is where the structural battery comes in. By building cars from batteries instead of adding them to existing structures, most of the added weight disappears. To a certain extent—that is, when all structural things are converted into batteries—increasing the car’s cruising range leads to almost no weight loss.
As you would expect-because I know you are sitting there thinking “What a great idea!”-there are obstacles to this clever solution. The first is to master the ability to make batteries from materials that can be used not only as anodes and cathodes for any basic battery, but also as strong enough-and very light! -A structure that can support a two-ton car and its passengers, and it is hoped that it will be safe.
Not surprisingly, the two main components of the most powerful structural battery to date-made by Chalmers University of Technology and invested by KTH Royal Institute of Technology, Sweden’s two most famous engineering universities-are carbon fiber and aluminum. Essentially, carbon fiber is used as the negative electrode; the positive electrode uses lithium iron phosphate coated aluminum foil. Since carbon fiber also conducts electrons, there is no need for heavy silver and copper. The cathode and anode are kept separate by a glass fiber matrix that also contains an electrolyte, so it not only transports lithium ions between the electrodes, but also distributes the structural load between the two. The nominal voltage of each such battery cell is 2.8 volts, and like all current electric vehicle batteries, it can be combined to produce the 400V or even 800V common to everyday electric vehicles.
Although this is a clear leap, even these high-tech cells are not ready for prime time at all. Their energy density is only a negligible 25 watt-hours per kilogram, and their structural stiffness is 25 gigapascals (GPa), which is only a little bit stronger than the frame glass fiber. However, with funding from the Swedish National Space Agency, the latest version now uses more carbon fiber instead of aluminum foil electrodes, which researchers claim have stiffness and energy density. In fact, these latest carbon/carbon batteries are expected to produce up to 75 watt-hours of electricity per kilogram and a Young’s modulus of 75 GPa. This energy density may still lag behind traditional lithium-ion batteries, but its structural stiffness is now better than aluminum. In other words, the electric vehicle chassis diagonal battery made of these batteries may be structurally as strong as the battery made of aluminum, but the weight will be greatly reduced.
The first use of these high-tech batteries is almost certainly consumer electronics. Chalmers Professor Leif Asp said: “In a few years, it is entirely possible to make a smartphone, laptop or electric bicycle that is only half the weight of today and is more compact.” However, as the person in charge of the project pointed out, “We It’s really only limited by our imagination here.”
The battery is not only the basis of modern electric vehicles, but also its weakest link. Even the most optimistic forecast can only see twice the current energy density. What if we want to get the incredible range that all of us have promised — and it seems that someone every week promises 1,000 kilometers per charge? — We will have to do better than adding batteries to cars: we will have to make cars out of batteries.
Experts say that temporary repair of some damaged routes, including the Coquihalla highway, will take several months.
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Post time: Nov-24-2021