In the middle of a packed afternoon with announcements from Tesla about innovations, the company strives to reduce the costs of electric vehicle production and energy storage through better battery design, the company says that it has made new advances in materials science for anodes and cathodes – important components in lithium-ion batteries all its products.
Tesla took an overall method to improve its battery from the manufacturing process that is still under development to the materials used in the cathode and anode, the basic building blocks of any battery system.
The result: a reduction in the cost of the cathode and anode materials, while increasing performance which on its own can extend battery life by 20%, says Tesla.
On the anode side, the company is looking at ways to integrate more silicon into its batteries by using metallurgical quality silicon. One of the most common materials on earth, most of the silicon used in microchips, batteries and even solar panels has been processed extensively with expensive treatments to make it work for various applications. With batteries, the question is its tendency to degrade when fully charged with lithium.
“With silicon, the cake crumbles and becomes sticky,”
Therefore, most companies use some form of treatment on silicon to make the material harder – or use as little silicon as possible in their batteries. “They enable some of the benefits of silicon, but they do not enable everything and they are not scalable enough,” said Andrew Baglino, the company’s SVP for powertrains and energy technology.
Instead of throwing out the silicon, Tesla said it is working on a new treatment method that can take cheap silicon of metallurgical quality and incorporate it into its new battery design.
“What we are proposing is a step change of capacity and a step change of cost and going to the raw metallurgical silicon itself,” says Baglino. “Design for it to expand [and] think about it in the electrode design … If you use simple silicon, it is dramatically smaller than the silicon used in batteries today.
Baglino expects that by using new treatment methods, the company can reduce the cost to $ 1.20 per kilowatt hour.
It is about starting with raw, metallurgical silicon that is stabilized with a cheap, elastic, ion-conducting polymer that is integrated in the electrode with a very elastic binder.
That innovation alone can increase the range of Tesla vehicles by 20%. “When we take that anode cost production, we see a reduction of 5% dollars per kilowatt at the battery pack level, says Baglino.
But the company does not intend to stop at the anode. It is also looking at using various materials science innovations to increase the efficiency of the cathode as well.
Both the anode and the cathode must be able to maintain their structure while charged particles bounce off. They are basically storage containers for electricity even when that electricity is moving – charging and discharging.
Baglino and Musk resembled the materials with bookshelves, where the charged particles are the books and the shelves are the cathodes.
Batteries in this analogy are basically libraries, where the cathodes store the books and the anodes are the librarians who move the books (energy) out into the world where they can be read or used (I think I have taken that analogy about as far as it can go).
“You need a stable structure to contain the ions. You want a structure that keeps its shape with ion. When you move the ion back and forth, you lose the life and the battery capacity drops very quickly, Musk says.
Several different materials can be used as cathodes, but the cheapest is by far nickel. It also has the highest energy density. But most batteries use cobalt because it is a more stable material.
Tesla said today that it is working on a way to stabilize nickel for use as a more robust storage material. This means that nickel can store energy (books) without the risk of overturning or degrading.
“We can get a 15% reduction in cathode dollars per kilowatt hour,” says Baglino.
Musk said that Tesla would not throw away its existing chemicals, but that the addition of new nickel-based batteries would enable the company to meet some of its other goals.
“We need a three-pronged approach to batteries,” Musk said. “Iron – medium range, nickel manganese as medium plus and high nickel for Cybertruck and Semi.”