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On the horizon (near and far): improved e-bike batteries

Published July 15, 2022

By Aidan O'Leary

A version of this article ran in the July issue of Bicycle Retailer & Industry News.

(BRAIN) — Super lightweight. Ten-minute charge time. Double the range. Less likely to burn down your store. If I could promise you all that in an e-bike battery, how quickly would you be putting in an order?

Recent developments in battery compositions and management systems promise huge improvements over the current industry standard, lithium-ion. And while some of the developments will take years to reach the e-bike market, some are nearly here. We reached out to researchers, e-bike brand owners, and battery experts to learn what's coming.

Key metrics

To get a sense of the key metrics for e-bike batteries, BRAIN spoke with Ravi Kempaiah, co-founder of Zen Ebikes and a postdoc at Dahn Lab at Nova Scotia's Dalhousie University. Kempaiah, in collaboration with Dahn Lab and Tesla, recently debuted findings on a new battery composition that has a better energy density and charge time than lithium-ion, all while approaching a theoretical longevity of 100 years. Kempaiah hopes to bring this new battery technology to market on Zen Ebikes next year.

"All you need is one fire to destroy your reputation, so safety is number one," Kempaiah said. He said stringent standards like UL certification will increase safety and the perception of safety, and thus, consumer confidence.

Kempaiah also zeroed in on longevity, which is key to sustainability. "This year, 2022, 40 million e-bikes will be sold. At our current rate of battery life, 2-3 years on average, by 2024, 2025, the world has to deal with 120 million kilograms of hazardous battery waste ... If all of that isn't recycled well or if it has to go through complex recycling, then the whole idea of sustainability goes out the window."

Kempaiah's third key metric is energy density. Unless new technologies are able to fit more energy into an equivalent amount of space, the batteries of tomorrow will be forced to weigh more, or deliver less range.

Finally, price is always key. Kempaiah said he's targeted an ideal of $500/Kwh for the end user. A Bosch battery system is currently around $1,550/Kwh.

Alternate chemistries

While Zen Ebikes pursues new materials, Kempaiah stressed that the transformation of e-bike batteries needs to be system-wide. Even the best battery chemistries depend on safe and effective management systems.

For other companies, like ZapBatt and their founder, Charlie Welch, advances made in battery management systems have opened the door for older battery compositions to be put to better use.

ZapBatt is aiming to bring its first product, a lithium-titanate battery pack, to market in the first quarter of 2023. The e-bike industry hasn't seen an LTO battery since the Schwinn Tailwind, back in 2008, but Welch said that the potential of LTO can be unlocked through new management systems. Their proprietary system will allow their battery to be retrofitted to a variety of motors with different voltages.

LTO battery cells promise lightning-fast charge times and longevity (up to 15,000 charge cycles according to the International Electrotechnical Commission), but energy density and cost are still factors. ZapBatt's initial offering will be a 360 Wh battery, weighing in at 9.5 pounds.

By those spec's, ZapBatt's battery has lower capacity and heavier weight than current lithium-ion offerings. And, the company estimates the packs will cost around $1,200-$1,600 per 500Whs. However, there are other metrics. Welch said ZapBatt batteries will offer greater value over time because of their longevity and efficiency.

Looking farther afield

When I asked Bosch USA's quality and compliance manager, Kunal Kapoor, what battery advance he was most excited to see in 5-10 years, he didn't miss a beat: "Solid state batteries are definitely looking interesting. They are safer, they are more powerful." A highly-prized peak of battery technology, solid-state batteries replace the highly volatile and flammable liquid electrolytes that allow the electrical current to flow between the positively and negatively charged parts of the battery with a solid electrolyte. This advance promises higher energy density, faster charge times, and much greater longevity, all while increasing safety. "If we use 50 cells in our battery pack today, if we go to solid state batteries, we may only have seven or 10 cells. That means smaller batteries with bigger range," said Kapoor.

The dawn of this new battery technology is surely rising, as tech giants like Samsung throw their money and energy behind it. They recently announced a breakthrough in their battery efforts, submitting a paper to Nature Energy demonstrating an all-solid-state battery that achieved a 50% reduction in weight compared to lithium-ion batteries, with an energy density of 900 Whs/L. This level of sophistication would smash any current metrics in the e-bike industry, and enable widespread proliferation of cheap, durable, and high-performance battery systems.

While Kempaiah is also excited about solid-state technology, he has a more tempered view of its prospects: "By the time that you hit the price point of current e-bike batteries (using solid state technology), you're looking at at least 2028." Although scientific advancements are undoubtedly critical to developing battery technology, there's a long distance to cover between the lab and the road.

A moment of gratitude

The batteries of the future are becoming less elusive, but in the meantime, it's worth celebrating what we currently have. "I don't think it's very far from ideal already," Kapoor quipped. "Bosch has the 625 Watt hour and the 700 Watt hour batteries. For a daily commute? I mean, we feel it's sufficient. And if somebody does have some more range needs, they can always carry an extra battery pack ... But we think that the technology is pretty mature and it's being used wisely and productively today."
There are definitely sustainability concerns around our current batteries, but the e-bike industry has quickly rallied to the cause, as major bike brands commit to recycling programs like Call2Recycle. Extending longevity is a great value-add for any battery system, but we can effectively manage our e-waste if we plan for it. While of course there are battery failures before this time, Kapoor noted that "You know, (longevity) is very subjective. How long does one expect a battery to last? ... Bosch generation one battery packs, which were introduced a little over 10 years ago now are still being used by consumers. So 10 years, in my view, is already a very long time for a battery pack to sustain."

The good news is that the battery developments of tomorrow only stand to bolster an already-efficient system. We can look forward to significant advances in the industry within the next year, but e-bikes are already creating a sustainable, efficient, and safe transportation alternative. "Interesting fact: 130 e-bike battery packs are equal to one EV (electric vehicle) battery pack," said Kapoor. When we honestly evaluate the state of the e-bike battery, it's clear that we're already living in a futuristic moment for our industry.

Topics associated with this article: Electric bike, From the Magazine

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