The million-mile battery is here, but it is not new.
Battery Day — September 22, 2020 — promises to be memorable for the future of electric vehicles. Its scheduled “great reveal” for sector-leader Tesla is just one in an impressive string of innovation that continues to break the mold of auto-making.
This elevated anticipation is justifiable: an invincible energy source for clean, powerful, trouble free motive enjoyment that lasts a lifetime is worth getting excited about. Because that’s the promise of the million-mile battery: at annual average driving distances 1,000,000 miles equates to a chronological lifetime of about 86 years.
It’s been a long time coming
Ever since Luigi Galvani twitched the nerve endings of a dissected frog legs with dissimilar metals in 1790, generations of scientists, researchers and entrepreneurs have chased a better battery. Alessandro Volta determined the true source of this new energy and primary battery cells were born — a single use package of metals and electrolytes with a limited lifespan that ultimately had to be disposed of.
We’ve come a long way since then. In terms of energy density (the total amount of usable electricity provided) the single-use, primary cell AA alkaline battery in your TV remote still compares favorably to leading rechargeable Lithium ion technology.
But the real difference is the ability to recharge and reuse.
Rechargeable batteries (secondary cells) have the convenience and economy to be used many times over. Recharging means simply reversing the flow of electricity and charge at a higher voltage to reverse the internal chemical reaction and restore the potential electric energy.
Longevity in rechargeable batteries is achieved by maximizing the number of charging cycles that a battery can withstand without losing significant capacity. The ideal mix of battery performance is a light, energy dense, stable, endlessly rechargeable package that is inexpensive to make.
Pay now or pay later, again and again
Cheap lead acid batteries dominate the rechargeable battery market — but they aren’t very good. Nearly every vehicle, including most modern electric vehicles, has one to power things like headlights, heated seats, windshield wipers, and navigation systems — the good old 12V battery. As a 12V source their only benefit is low cost, and any car owner will tell you they don’t last very long and usually fail without warning.
Lithium ion batteries (which first appeared in the 1980s) provided higher energy density and higher cycle life compared to their lead acid ancestors. Combined with more efficient electronic circuits and digital wireless data transmission, lithium ion batteries have enabled our mobile phones to evolve from a phone in a briefcase to the 21st century marvels, such as two-day powered smart phones, watches as smart phone extensions and the expanding universe of wireless internet of things.
But to power cars, there is a minimum energy threshold for consumer utility. The first generation of electric cars circa 1900 ran on lead acid batteries, but their range was limited, and their top speeds rarely exceeded 25MPH (more on them later).
Today automobiles are much heavier for safety reasons. Today’s cars, minivans and trucks require thousands of times more energy than consumer electronics to match the range provided by internal combustion engines. Without that range, modern production electric cars would never reach the tipping point for broad market adoption.
Lithium ion, repurposed from the computer laptop industry, was the chemistry that catalyzed the electric car renaissance of the 2010s. Ten years on there is a race for the illusive ultimate battery, and hopefully before battery and automakers invest heavily in the production lines required to fulfill the expanding demand in our automotive future.
Even though we’re past the first decade of widely available electric cars, we still aren’t sure of the actual useful life of current EV batteries. Industry-standard eight year warranty periods have fared well for the average consumer and for automakers, but we don’t know much about life beyond eight years of service. And prospective buyers still worry about the cost of replacing batteries, assuming they’ll still own the vehicle a decade later.
Now Tesla has thrown down the gauntlet with a promise of the million-mile battery. There’s lots of speculation and debate about what it will take to get there. Are we talking about solid state batteries? Graphene electrodes? Nano technology? Dual-carbon compositions?
What if the million-mile is already here, and has been for more than a hundred years?
Back in the 1890’s, the first wave of electric cars relied on rechargeable secondary cells, at that time limited to lead acid technology. That wasn’t good enough for the Elon Musk of the day, the technology prolific Thomas Edison, who commercialized another chemistry based on a nickel iron formulation.
Packed in steel cases (and filled with a readily available electrolyte, potassium hydroxide) these batteries were 42% more energy dense than lead-acid, and offered virtually unlimited life. Edison began selling these batteries in 1911 for a short time to the Anderson Electric Car Company, producers of the high brow Detroit Electric car.
Coveted by urban socialites of the day, Detroit was the car of the fairest of high society. Clara Ford, wife of Henry Ford was a prominent owner. Electric enabled starting a car at the pull of a lever without having the indignity of cranking an engine; it was silent; and it did not spew untreated exhaust like their combustion competitors.
Edison’s batteries were a premium option. On a base price of $2,600 for the Detroit Electric, the Edison battery added $600 to this three-passenger coupe. Putting that in the perspective, the Edison battery alone was the same price of a Model T, or a teacher’s annual salary. The total price of the car was equivalent to a small mansion. As it turns out it may have been worth it.
Edison was a tireless promoter of his technology.
Legend has it that on a hot July day in 1910, he demonstrated the exceptional range provided by the premium batteries. A Detroit Electric car, fitted with Edison’s nickel iron battery cells, drove for 211 miles on a single charge.
Quite likely this is more than legend. Given the optimal warm summer temperatures, level ground and the fact that the Detroit only traveled at a maximum of 25 MPH, it is believable that this story is a true report, despite Edison’s reputation as a master promoter. But how durable was this technology? Would it last?
Have we already achieved the first million-mile battery?
Testing in a lab or on prototypes is one thing. Promotions are another. But are there any examples of batteries that could be useful over a span of eight decades?
Since 2006 I’ve been privileged to be part of a caretaker group of a 1912 Detroit Electric owned by the Vancouver Electric Vehicle Association. This car had these premium Thomas Edison batteries fitted as original equipment.
The original nickel iron batteries lasted seventy-eight years — until 1990. By then, the steel casings had degraded so they no longer held the potassium hydroxide liquid electrolyte that was part of the secret to their longevity. Our research revealed that the usefulness of the original batteries was maintained by simply replacing this inexpensive electrolyte. Once a decade would do.
We weren’t the first to appreciate the longevity of nickel iron batteries. In the historical record of our Detroit, there’s a 1936 letter from by the Thomas Edison Battery Company to the original owner, who had written previously to state how pleased they had been with the 24 years trouble free service the batteries had already provided.
In 2020 a replacement set of nickel iron batteries have been acquired for VEVA’s 1912 Detroit, restoring the original factory voltage to the car, and encased in custom made maple wood containers matching the Detroit original factory production 108 years ago as close as possible. VEVA expects this contemporary recreation to outlive the originals and still provide useful motive power in next set of ’20s, the 2120’s.
Are there other ways to get to a million-mile battery?
While various chemistries and electrode configurations provide different longevity and energy densities — could we still obtain a million-mile battery from the chemistries currently in mass production?
As it turns out, yes.
One way to achieve superior longevity is a larger battery, such as exactly what Tesla adopted early in their vehicle production. A larger battery means that fewer full cycles will occur to go a specified distance. Tesla was already well on its way to the million-mile battery and may already be there with its latest production batteries of the Models 3 and Y. Build a large enough battery that carries the vehicle the distance within its cycle life, and voila!
Another way is to limit those full charge and discharge cycles — keep the battery in the middle range of state of charge. Studies have shown that battery degradation when cycling between 80 and 30% depth of charge is negligible. Therefore, another possibility emerges. On-board or on-route charging. That’s old news with gasoline generators, as demonstrated with GM’s serial hybrid, the Chevy Volt or BMW’s i3 REx (Range Extension). But the maintenance of these internal combustion solutions are retrograde to the spotless maintenance routine of electric drive.
Zero emission / low maintenance opportunities exist with on-board charging alternatives such as fuel cell range extension. Not fuel cells as “load following” with a small battery pack — this creates inefficiencies for both battery and fuel cell that make them expensive and less reliable. But right sized fuel cells that are run at their optimum efficiency level, and only when preset state of charge charging algorithms are triggered. The concept is to reduce the number of cycles for battery longevity, while at the same time provide flexible range extension of up to 3X battery capacity.
This solution may not be necessary for consumer cars — we are basically there already there for long trips and for the cumulative 1,000,000 miles, and dual energy systems are awkward for consumers. The fundamental range extension application will be for heavy duty vehicle fleets that will require a 1:1 interoperability with existing diesel.
Other range extended applications will include consumer vehicle segments of long range electric RV’s, electric pickup truck owners who need to tow a weighty trailer across mountain passes, have significant power take-off, or cold weather use that could benefit from co-gen heat production to ease the load from — and optimally warm — traction batteries. Range extended batteries of all sizes could potentially be million-mile.
The future looks bright for the million-mile battery, as it has since 1912.
John Stonier, CPA, CA is the President of the Vancouver Electric Vehicle Association, and a long time electric vehicle enthusiast, builder, owner, driver and entrepreneur.
 Based on average miles driven 2018 Federal Highway Administration, Highway Statistics, Table VM-1 http://www.fhwa.dot.gov/policyinformation/statistics/2018/pdf/vm1.pdf
 New Atlas July 8, 2012 https://newatlas.com/scientists-give-new-life-to-thomas-edisons-nickel-iron-battery/23102/