Enovix, based in Fremont, California, announced that it demonstrated in electric vehicle (EV) battery cells the ability to charge from 0% to 80% state-of-charge in as little as 5.2 minutes and to achieve a greater than 98% charge capacity in under 10 minutes. The cells also surpassed 1,000 cycles while retaining 93% of their capacity.
The achievement shattered the United States Advanced Battery Consortium (USABC) goal of achieving 80% charge in 15 minutes.
Other goals for USABC at the cell level include a usable energy density of 550 Wh/L, a survival temperature range of -40 to +66 degrees C, and a cost of $75/kWh at an annual output volume of 250,000 units. A full set of USABC targets can be found here.
The company demonstrated the fast-charge ability in its 0.27 Ah EV cells in its silicon lithium-ion batteries, which it said contain a novel 3D architecture and constraint system. The cells contain a 100% active silicon anode. Enovix said the material has long been heralded as an important technology in the next generation of battery anodes.
Silicon anodes can theoretically store more than twice as much lithium than the graphite anode that is used in nearly all Li-ion batteries today (1800mAh/cubic centimeter vs. 800mAh/cubic centimeter).
“Fast charge capability can accelerate mass adoption of EVs and we’ve been able to demonstrate a level of performance that meets and exceeds many OEM roadmaps,” said Harrold Rust, co-founder, CEO and president of Enovix. “EV manufacturers are in pursuit of batteries that support longer range, while the public and private sectors work to increase EV driver access to fast chargers. We’re proud to support these goals to help electrify the automotive industry and demonstrate our batteries are an exciting option to power long-range, fast-charging EVs.”
Silicon’s high energy density, however, creates four significant technical problems that Enovix has addressed with its technology:
- First Charge Expansion: The cells have a stainless-steel constraint system surrounding it that limits the battery from swelling. Enovix reorients the electrodes to face a small side of the battery to decrease the required constraining force.
- First Charge Efficiency: The battery uses a “pre-lithiation” process during manufacturing to insert additional lithium source to top-off lithium trapped at formation. The batteries can do this practically because the additional lithium only needs to travel a short distance in the 3D architecture to permeate the anode.
- Cycle Swelling: Enovix manages swelling as a result of cycling with its integrated constraint, limiting swelling to as little as <2% cell thickness after 500 cycles.
- Cycle Life: The integrated constraint keeps particles under constant stack pressure, limiting particles from electrically disconnecting and cracking.
“Our unique architecture enables a battery that not only charges in less than 10 minutes, but also maintains high cycle life,” said Ashok Lahiri, co-founder and CTO of Enovix. “We can improve battery performance today using the same chemistries, but more importantly, we can accelerate the industry’s roadmap.”
Lahiri will speak at the 12th International Advanced Automotive Battery Conference (AABC) Europe in Mainz, Germany. His presentation at 11:20 a.m. CEST (5:00 a.m. EST) titled “Silicon-Anode Lithium-Ion Batteries for EV Applications,” will provide an update on the company’s EV program. The slide deck can be found here.
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10-minute fill up. 100 kilo watt hours of charge in 10 minutes or 600 kilo watt hours in just one hour. That would take a 600-kilo watt capable service to the outlet. At 250 volts, it would need 150-amp minimum serge or 200-amp optimal feed of 2-#2 AWG pure copper wires in open air and #1-0 AWG in conduit to each charge station. The current #6 copper cables, on 3rd stage charging, would just burn up. You would need a 400-amp service installed at a residence so this most likely would be for standalone fast charging at rest stops, filling stations or fast-food restaurants. However, all existing modes of charging would work, and this could be the killer of the argument against long distance driving in an EV. The fact that the battery showed some degradation after only 1000 charges or three years of daily charging, having a lower cost replacement battery available than the current $22,000.00 Lithium-ion Batteries would be advisable. If a standard ICE vehicle uses $2,400.00 worth of gasoline each, driving 12,000 miles on $6.00 gasoline, at 30 miles per gallon, for a year for 5 years and an electric vehicle uses $960.00 of electricity a year using 4,000 kilowatts of electricity at 24 cents per kilo watt hour. of electricity each year for 5 years. Then $12,000 – $4,800.00 = $7,200.00 for the replacement battery just to be equivalent after 5 years of use. Any more expensive than $1,440.00 per year pro-rated for replacement batteries, then people will not want to switch to electric vehicles unless forced to by the government.
I appreciate your calculations Edward, however I’m not sure the batteries would need to be replaces that often in real life use.
Perhaps I’m wrong, but I assume “The cells also surpassed 1,000 cycles while retaining 93% of their capacity.” was the result of charging at or near the fastest rate.
Most EVs are charged at home for the majority of their cycles, so wouldn’t the lower rate mean longer life?
Perhaps your calculations would apply more to commercial vehicles like semis that would require more fast charging.
Here in the San Francisco Bay Area, workers commute 75 to 125 miles, each way, from the central valley because home prices are so high here. Most new EV cars have battery capacity ranges of 240 to 360 miles and those commuters, with 200-mile round trips would be required to get “fast charging “daily. These drivers also rack up 36,000 to 50,000 miles or more annually in commuting. Even those “closer in” rack-up 120 miles a day and would need to do level 2 – 240 volt charging overnight. I am concerned about the price of the batteries, cost of replacement batteries and how often they would need to be changed out and of course, the weight of the batteries that have to be steel encased.
People who drive those kinds of miles, also tend to get a new car every 3 to 5 years. Repairs become a major expense on cars with over 150,000 miles and tend to be traded in on newer, safer and better-looking ones. If an electric car could get 500,000 miles over 10 years before any major battery or motor replacement, it could sell the EV industry in people’s minds. Tesla has a few customers like that that give testimonials but also get one or two battery replacements. With some under warranty, the battery replacement was an inconvenience but when the battery had to be purchased, it was another matter. Just like the Transmissions that I needed to re-build or replace, the cost of keeping the car has to be compared to the Kelly Blue Book values. What would the Kelly Blue book value an EV with 6-year-old, 100,000-mile driven batteries?
I have 67 kilo watt hours of deep cycle marine/RV batteries powering my home and I have to replace them every 6 years. That cost is $7,200.00 and I have to budget that into my electrical costs. Since it replaces $15,000.00 or more of grid tied electricity, it is worth it to keep buying them since the solar panels have already paid themselves off. Since Electric Cars depreciate faster than a 25-year Guaranteed rooftop solar system, batteries will become the determining factor on re-sale value and longevity.
“The fact that the battery showed some degradation after only 1000 charges or three years of daily charging…”
Each time you plug it in, is not a “charge”. A “charge” is each time you go from 0%-100%. So, if each time you plug it in, you only add 10% charge, then it would take 10 plug ins to equal 1 “charge”.
As for “some degradation”, all rechargeables suffer some degradation with each use. Only 7% degradation after 1,000 full charges is less than 1/2 the rate of the best rechargables currently in use, and not nearly enough to require a replacement.
“this most likely would be for standalone fast charging at rest stops, filling stations or fast-food restaurants.”
Why would you need fast charging at home or the office. The “in the Bay Area we commute” is silly, since most offices would have charging stations that would fill you back up over the 8 hours or more that you work. The $22k number for replacement is just not correct. Based on you assumptions, why didnt you include things like oil changes or I dont things like TRANSMISSIONS or ENGINES or MUFFLERS, or RADIATORS or BELTS or HOSES in your calculations.
None of this belies the fact that they said after 1000 cycles it was STILL at 93%. Let’s say the 100% is 300 miles and we take it down to 90% you are STILL at 270 miles.
The person who claims a 50% loss in the winter must not be a very good driver. My reduction in range is 10-15% at MOST on the coldest of days
I did not notice any data in the article addressing charging and range issues with cold weather. At least half of the population lives in states where the temperature drops below freezing in the winter. The range of Tesla batteries drops up to 50% when driving in cold weather which then doubles the cost of charging not to mention the need for more charging stations.
Hopefully an update to the article can address temperature and it’s affect on range and charging.