Most future technologies such as artificial intelligence, edge computing, 5G, electric vehicles, augmented reality and virtual reality all require higher battery energy density. Building and scaling a battery that includes a 100% active silicon anode has long been an industry goal because it dramatically increases energy density and performance.
Enovix Corp., a Fremont, CA-based developer of next-generation lithium-ion batteries with silicon anodes, has developed a proprietary cell architecture that enables a 100% active silicon anode, resulting in a battery with high energy density and long lifespan fast charging without compromising security. Enovix is building an advanced mass production facility for lithium-ion batteries with silicon anodes in the United States.
For this article, EP&T Magazine spoke to Ashok Lahiri, co-founder and chief technology officer of Enovix, who has served as a technical advisor to the company since February 2023. Prior to this role, he had been the company’s Chief Technology Officer since co-founding Enovix in 2007. Lahiri was the lead architect of Enovix’s 3D rechargeable silicon lithium-ion battery and was responsible for the design and implementation of the patented 3D cell architecture and the Company’s high performance silicon anode.
Enovix believes it has the next big advance in battery technology. Describe the company’s proprietary cell architecture that increases energy density and maintains high cycle life.
Enovix reinvented battery architecture by replacing the jelly roll design seen in many traditional batteries with an innovative stack design. The jelly roll architecture consists of rolled anode, separator and cathode sheets which wastes volume due to lack of precision and the fact that a round object is placed in a rectilinear package. The Enovix cell architecture instead stacks its cathodes, anodes and separators side-by-side, allowing for more efficient use of battery volume, resulting in improved overall energy density and the ability to use a 100% active silicon anode.
Most conventional lithium-ion batteries often use graphite anodes. However, at Enovix we use 100% active silicon anodes. Silicon is an abundant and sustainable ingredient that theoretically can store more than twice as much lithium ion as graphite. The use of silicon results in a high energy density battery in an efficient form factor. Enovix also uses an onboard constraint system to keep the cell under constant pressure, preventing the electrodes from separating and breaking and improving battery life.
Source: Enovix Corp.
What makes the Enovix battery so unique from what is currently available on the market?
The architecture of Enovix batteries is something the industry has never seen before. For decades, the industry made batteries in much the same way, working to improve the materials and chemistry within the battery, until Enovix’s 3D architecture deviated from that paradigm. Our background in 3D architectures, combined with our passion for problem solving, convinced us that we could produce the next generation Li-ion battery. Replacing the traditional jelly roll design with a precision laser-cut design featuring stacked anodes, separators and cathodes, Enovix cells allow for more efficient use of battery volume.
The architecture also enables a breakthrough in lithium-ion battery safety called BrakeFlowTM. The Enovix 3D cell is divided into many sub-cell units, each containing a small fraction of the battery’s energy and each having a discrete connection to a common anode or cathode bus bar. Each sub-cell is connected to the common bus bar via the BrakeFlow system, which is designed based on the number of electrodes and the area of each electrode to limit the discharge current from the rest of the cell through the short-circuited sub-unit. If BrakeFlow is working properly, the power dissipated at the short should not raise the temperature around the short location enough to trigger a thermal runaway. With integrated BrakeFlow, instead of a sudden, catastrophic release of energy, the battery discharges slowly and safely.
Why was it so difficult to make up to this point?
Manufacturing is often one of the more difficult stages in developing a unique technology, especially when the tooling isn’t already in place. Multiple iterations of tooling are often required before the required efficiency is achieved. This isn’t unlike what many other industries like solar or semiconductors have been through. With each subsequent iteration, the manufacturing process became more and more efficient. Therefore, based on what we learned from our Gen1 toolset, we predict that our Gen2 toolset is likely to perform significantly better.
How does the architecture of this Li-ion battery technology make it smaller, more energy dense and more environmentally friendly?
Our batteries have a 100% active silicon anode. Silicon is an abundant and sustainable ingredient that can theoretically store more than twice as much lithium ion as a graphite anode used in most conventional Li-ion batteries today. Using silicon in our battery architecture results in a battery with higher energy density and an efficient form factor.
When you need a battery with a specific amount of energy, packing more energy into the same form factor results in less waste of the cell’s inactive materials such as the packaging.
Which design segments do you expect to see most often for this technology?
We initially focus on serving our customers who make small, portable consumer electronics, and then move to larger cells for devices such as mobile phones and laptops.
What types of consumer electronic devices are most likely to use this type of battery?
We believe that the technologies of the future need a better battery, from wearables to electric vehicles. We work with some of the world’s largest consumer electronics companies – including Samsung and others.
Where is the manufacturing facility and when will the electronics design community have access to this technology?
Enovix’s first manufacturing facility is located in Fremont, California (called Fab1). We announced in our November 2022 letter to our shareholders that we have shipped qualifying cells from Fab-1 to customers in many consumer electronics applications. In the future, our goal is to have devices with Enovix batteries on the market.
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Ashok Lahiri, co-founder and chief technology officer of Enovix.
Enovix Corp. is a leading innovator in the development and production of advanced silicon anode lithium-ion batteries. The company’s proprietary 3D cell architecture increases energy density and ensures long life.
