The search for the better battery is going on in laboratories around the world. On Tuesday, Tesla unveiled its new 100 kWh battery, which for the time being will only be available in performance versions of the Model S and Model X equipped with what the company call Ludicrous Mode. Tesla says it expects about 10% of new Model S sales will be the P100D with Ludicrous. The battery is not expected to become generally available until next year.
The Model S P100DL retails for a shade under $160,000. Elon Musk makes no apology for the high cost of the new technology. Apparently, 100 kWh is the maximum energy that can be packed into the space available in the Model S chassis, using current battery chemistry. Besides, Elon says, the profits from the new model will go to fund the development of the Model 3 due out at the end of next year. The plan, apparently, is to soak the rich to fund the arrival of the first “affordable” Tesla. There are indications there are plenty of wealthy people lining up to be sheared — all in the interest of moving the electric car revolution forward.
While the press is going gaga over the Tesla announcement, virtually no attention is being paid to research by a team of researchers at Penn State who say they have developed the “ideal” energy storage medium for electric car batteries. The report is fairly technical, but the gist of it is that the work, which is funded in part by the US Office of Naval Research, has created a polymer dielectric material that has high energy density, high power density, and excellent charge/discharge efficiency, making it highly suitable for use in electric and hybrid vehicles. Their findings were published on Monday in the Proceedings of the National Academy of Sciences.
The key is a unique three dimensional sandwich-like structure that protects the dense electric field in the polymer/ceramic composite from dielectric breakdown. “Polymers are ideal for energy storage for transportation due to their light weight, scalability and high dielectric strength,” says Qing Wang, professor of materials science and engineering and the team leader. “However, the existing commercial polymer used in hybrid and electric vehicles, called BOPP, cannot stand up to the high operating temperatures without considerable additional cooling equipment. This adds to the weight and expense of the vehicles.”
“That’s why we developed this sandwich structure,” Wang says. “We have the top and bottom layers that block charge injection from the electrodes. Then in the central layer we can put all of the high dielectric constant ceramic/polymer filler material that improves the energy and power density.” The outer layers, composed of boron nitride nanosheets in a polymer matrix, are excellent insulators, while the central layer is a high dielectric constant material called barium titanate. “We show that we can operate this material at high temperature for 24 hours straight over more than 30,000 cycles and it shows no degradation,” Wang says.
See? I told you this was technical stuff. Don’t say you weren’t warned. The new material, call SSN-x (the x refers to the percentage of barium titanate nanocomposites in the central layer) has essentially the same charge/discharge energy at 150º C as BOPP has at 70º C. That means a battery using the new material can be smaller and lighter. Just as important, it needs less cooling than traditional batteries. The need for cooling is one of the critical factors keeping Tesla from making a battery larger than 100 kWh fit into the Model S.
Now we come to the tricky part — commercializing the discovery. “Our next step is to work with a company or with more resources to do processability studies to see if the material can be produced at a larger scale at a reasonable cost,” Wang says. “We have demonstrated the materials performance in the lab. We are developing a number of state-of-the-art materials working with our theory colleague Long-Qing Chen in our department. Because we are dealing with a three-dimensional space, it is not just selecting the materials, but how we organize the multiple nanosized materials in specific locations. Theory helps us design materials in a rational fashion.”
The electric car revolution, in which even ordinary people can afford to drive on electrons instead of fossil fuel, just got one step closer to reality.
Source and photo credit: Electric Cars Report