Make sure you show this article to everyone who says lithium-ion battery technology cannot evolve much more. One of the major safety issues they present has been addressed in an incredible way by Soteria. Not only that: the solution will soon be available to customers through SVOLT. What these companies promise is that you will not hear about thermal runaway with their cells, as the video above shows.
A short circuit normally causes these events in batteries. When it happens, it increases the temperature inside the cell, melting the separators and putting the cathode in direct contact with the anode, which produces even more heat. When a battery is affected, it causes the same problem in the nearby cells, which results in catastrophic fires in electric vehicles.
According to Soteria, that’s because current batteries are conceived in the wrong way. They have robust metal current collectors that can deliver the energy of the entire cell to the short circuit, either caused by a defect – such as in the Hyundai Kona Electric recall – or by dendrites, which perforate the separators.
Soteria inverted the situation: it created thermally unstable metal current collectors and a stable separator. The video below compares how regular separators behave in the presence of heat compared to the separator Soteria created.
The separators in the middle and to the left are made of ceramics and plastic. The one to the right is Dreamweaver, the material Soteria developed. You can see how the plastic and ceramic separators immediately shrink and disappear in the presence of fire. Dreamweaver burns, but it does not shrink nor melt. In other words, it is still there doing its job of separating the anode and the cathode.
Dreamweaver is a non-woven paper-based product. While a plastic separator resists only 110ºC (230ºF) to 130ºC (266ºF), the Soteria separator resists 300ºC (572ºF). It can use aramid fibers to increase that thermal resistance to 550ºC (1,022ºF). Its composition helps to accelerate cell formation. Check how much faster it allows the liquid electrolyte to spread. According to Soteria, it’s 40 times faster.
Regarding the electrodes, Soteria replaced the solid copper foil on the anode side and the solid aluminum foil on the cathode side with plastic. In other words, instead of the solid copper foil coated as the anode, it uses a copper metalized plastic. On the cathode, you’ll find an aluminum metalized plastic as well. The active materials that coat the solid metal foils are still there.
When there’s excessive heat in any part of the cell, the thin metalized plastic film melts in the region where it is affected. That makes it work like a fuse in the part where the defect happened. Since the Dreamweaver separator is still doing its part, the battery continues to work. The drone below, with a perforated Soteria cell, proves that.
Critics may say this is all theoretical and that consumers will have to wait to benefit from these innovations, but that is definitely not the case. We learned about Soteria due to a joint press release with SVOLT. The Chinese battery manufacturer announced cells with these improvements would be up for sale in the third quarter of 2021.
Neither entity disclosed any electric car to present these news cells so far. However, we’re sure it will not take long before we learn of the first vehicle to get them.
According to Soteria, its tech is compatible with various chemistries such as NMC811, NMC523, NMC622, LFP, LCO, etc. Soteria also stresses that it is not a company but a consortium of companies that aims to license these materials and production methods to as many cell manufacturers as possible. This is why its full name is Soteria Battery Innovation Group. Consortium members have already produced a variety of pouch cells “anywhere from 1Ah-25Ah and 60Ah,” apart from “18650s and 21700s on the cylindrical side.”
In terms of production expenses, the Dreamweaver separator either costs the same or a little less than conventional materials. When it comes to the thin metalized plastic films, they remove 90 percent of the metal used in today’s batteries. That implies these cells are lighter and less expensive to manufacture.
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The consortium also wants to establish “aggressive test standards” to highlight how much safer Soteria batteries can be and get these standards adopted worldwide. If the concept proves to be successful, all current electric cars may become obsolete.
Gallery: Soteria BIG Develops A Thermal-Runaway-Free Lithium-Ion Cell
Customers may start to ask why risk driving something that can burn to the ground should anything go wrong when Soteria batteries can eliminate that risk. It seems even solid-state batteries may need to up their game before it even started: Soteria batteries already present one of their biggest advantages.
Source: Soteria BIG via Green Car Congress