Q&A: Semiconductor experts create a new, better battery

Frits Bliek, CEO of Dutch startup Ocean Grazer, explains an “ocean battery,” during the Consumer Electronics Show (CES) on January 6, 2022 in Las Vegas – Copyright AFP/File Heather SCOTT

The next big advance in battery technology comes from semiconductor experts. A small cadre of chip experts, some who had worked together since the 80s, took a hard left when they realized that the battery, not the chip, would enable the most important technological advances of the 21st century.

to gain understanding Digital Journal interviewed Ashok Lahiri, co-founder and CEO of Enovix.

Digital Journal: What are the limitations with the current generation of batteries?

Ashok Lahiri: Energy density improvements in lithium-ion batteries have not kept pace with the needs of mobile electronics, which can limit their use and functionality. Technology of the future—Artificial Intelligence (AI), Edge computing, 5G, Electric Vehicles (EV), Augmented Reality (AR) and Virtual Reality (VR)—all require a battery with high energy density.

DJ: What types of batteries are needed for future government technology?

Lahiri: Future technologies require very high energy density batteries and, in some applications, such as EVs, very fast charging times. But as energy density increases, safety should be at the fore.

Battery designers have found that when they try to increase energy density, they can compromise safety, and vice versa. The Enovix 3D Silicon Li-ion cell architecture elevates the conventional paradigm and enables both an increase in energy density and a high level of abuse tolerance to reduce the risks of an internal short circuit leading to thermal runaway or fire.

DJ: What is the project you have been working on?

Lahiri: Enovix currently ships commercial batteries from the world’s largest consumer electronics companies. We continue to expand our global reach and have active engagements across Asia, including with leading smartphone OEMs in China and major consumer brands in Japan and Korea, including Samsung. We also have an agreement with the U.S. Army to build and test custom cells for use within the U.S. Army soldiers’ central power source.

DJ: What were the main technological challenges?

Lahiri: The battery industry was entrenched in decades of experience building batteries essentially one way, with incremental innovation with better materials and chemistry. To break out of this paradigm, someone would have to do something completely different, and it would not be easy. We felt our background in 3D semiconductor architectures could be such a game changer. However, we recognized that even with our decades of combined experience and expertise, designing, assembling and manufacturing an entirely new Li-ion battery would be very challenging. Our passion for solving difficult problems and a collective belief that the world desperately needs a better battery helped us develop and manufacture the next generation Li-ion battery.

Historically, advances in battery performance have come primarily from improvements in the active cathode and anode materials of the battery. While other companies focus on incrementally improving batteries through new chemistries, we completely reimagined the battery architecture – throwing out the more than 100-year-old “jelly roll”, where long strips of anode, separator and cathode are wound together in a jelly roll shape, and replace it with a precise, laser-cut design where short strips of anodes, separators and cathodes are stacked. This new design allows for more efficient use of the volume of the battery as opposed to the jelly roll, where significant volume is wasted at the corners and in gaps in the middle of the battery, given the lack of precision in the wrapping process.

Our new 3D battery design improves the packaging efficiency of the active material within the battery, enables exceptional thermal performance and abuse tolerance, and accommodates the use of a 100% active silicon anode. Silicon is an abundant and sustainable ingredient that can theoretically store more than twice as many lithium ions as a graphite anode, which is used in most conventional Li-ion batteries today. The use of silicon within our battery architecture translates to a battery with high energy density in an efficient form factor

DJ: Challenges; how do you handle safety?

Lahiri: In a commercial Li-ion cell manufactured for consumer electronics, external heat, overcharging, or an internal or external short circuit can lead to thermal runaway. There are many ways to reduce the risk of an internal short circuit; however, the industry could not prevent all incidents.

The Enovix 3D cell architecture incorporates many features within the cell to improve electrical, physical and environmental abuse tolerance. These features reduce the potential of an internal short circuit. In the unlikely event that an internal short does occur, Enovix BrakeFlow™ technology adds an extra layer of protection to further reduce the risk of thermal runaway. With BrakeFlow built in, the battery is designed to discharge slowly and safely instead of a sudden catastrophic release of energy.

DJ: When will the batteries be available on a commercial scale?

Lahiri: We announced in June 2022 that we shipped our first commercial batteries from Fab-1 production line. While we cannot predict our customers’ product release schedules, we announced in our Q3 2022 Shareholder Letter that we have shipped production cells to 25 OEMs. Furthermore, our Gen2 Autoline, which we view as the engine that will drive our manufacturing scale-up in the future, is expected to be qualified in the first half of 2024 and 2024.

DJ: What other innovations are you working on that you can share?

Lahiri: We launched a new business unit to adapt our 3D battery architecture to the EV market called Enovix Mobility. It is early in our development, but we are pleased with the results so far with our EV test cells.

During the third quarter of 2022, we continued to see excellent data supporting high cycle life and high calendar life – two characteristics that have historically held cells back with silicon anodes. As part of our three-year Department of Energy grant program that pairs a 100% active silicon anode with EV-class cathode materials, our test cells surpassed 1,500 cycles while retaining 88% of their capacity – well ahead of the Department of Energy’s program goal of 1,000 cycles with 80 percent capacity retention. Additionally, our test cells used under extreme temperatures retained enough capacity to allow us to comfortably model more than 10 years of calendar life, a key requirement for EVs.

In June 2022, we announced that we had demonstrated the ability of our EV test cells (0.27 Ah cells) to charge from 0-80 percent state of charge in as little as 5.2 minutes and a more than 98 percent charging capacity in less than 10 minutes.