Since the layout of the 4680 large cylindrical lithium-ion battery, Tesla has been working hard to develop the battery dry electrode manufacturing process, but progress has been slow. However, the USPTO recently granted it four patents, meaning Tesla's breakthrough in this field.
Of the four patents, two were issued in January of this year. One is for a dry electrode film and a micro-particle non-fibrous binder that can improve battery life. One is a new electrode binder that can withstand higher operating voltages without being rapidly degraded.
On February 2, local time, the USPTO published two more patent applications filed by Tesla related to dry electrode technology. The first is a "mixture of metallic elements and carbon for energy storage devices", which can be used to make a dry electrode film. The film includes lithium metal and carbon particles, porous carbon particles, and a solid electrolyte interface (SEI) layer.
The second patent application is a method for more convenient preparation of 3- r -1,4,2-dioxazol-5-one compounds. This is an electrolyte additive that can significantly extend the life of lithium-ion batteries during long cycling times. The two patent applications are due to be filed in June and August 2022, respectively.
One of Musk and Tesla's promises when they launch the 4680 large cylindrical battery in 2020 is that the battery will use silicon negative electrodes instead of graphite negative electrodes and a new battery manufacturing process that will dramatically improve battery performance and reduce production costs while extending battery life.
This technology is dry electrode (DBE) manufacturing technology, which is considered the holy grail of lithium-ion battery processes.
Dry electrodes are also the main reason Tesla is acquiring Maxwell in 2019. Maxwell uses this technology to make supercapacitors, but Tesla thinks it can be transplanted to the 4680 battery manufacturing process.
Two years later, Tesla sold Maxwell's ultracapacitor business, but kept the dry electrode technology.
It is understood that the difference between dry electrode technology and traditional wet electrode technology is that the wet method requires the use of solvents, and the process involves mixing negative and positive electrode material powders with solvents and then coating them onto a metal collector to dry. In contrast, the dry method does not require a solvent, and the electrode material powder is pressed directly onto the metal collector to form the electrode. Compared with the wet method, the dry electrode manufacturing technology does not require a large plant footprint to dry the solvent, which greatly reduces the capital and manpower expenditures required for the plant, and is more environmentally friendly.
In July 2021, Musk tweeted : "Dry electrodes are one of the keys to lowering the cost of lithium batteries", but Musk also said, " Maxwell's concept requires a lot of engineering and validation to achieve high quality mass production of batteries, which we have not fully achieved. "
In fact, until today, Tesla to also has not yet fully overcome this fortress. That's because the uniformity and consistency of dry electrode film formation is more difficult to control than the wet process, and the electrodes of electric vehicle batteries are larger and thicker than those of supercapacitors, making them more difficult to produce.
But these recent patents granted to Tesla by the USPTO suggest that Tesla may be closer than ever before.
Not only that, but the production of dry electrodes for the 4680 battery has recently received a heavy-handed boost. Just recently, Tesla installed two huge presses in the battery manufacturing department of its Giga Texas. The presses, manufactured by Italy's Sacmi Imola, weigh 334,000 pounds each, roughly three times as much as Tesla's original raw material presses. Sources close to the situation speculate that the two machines will most likely be used for the production of dry electrodes.
If the speculation is correct, this means that Tesla is continuing to surge toward mass production of the 4680 battery.