A battery-free e-bike: Pi-Pop pioneers e-bike supercapacitor tech

A battery-free e-bike - Pi-Pop pioneers e-bike supercapacitor tech

The French-designed Pi-Pop e-bike looks more like a basic shared city electric bike at first glance.

However, this Pi-Pop battery-free e-bike features a unique electric boost system that ditches the battery pack found on traditional e-bikes in favor of a more flexible supercapacitor boost system that collects energy on level ground and downhill, and drains it through pedal power on uphill climbs.

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    Know the brand: Pi-Pop

    The Pi-Pop is a French innovation that promises to revolutionize Europe’s rapidly expanding market for importing more than six million bicycles.

    Brussels wants 2024 to be the year of cycling. The challenges of climate change and urban decarbonization are pushing everyone to move to more sustainable modes of travel. Bicycles are at the top of the list, especially e-bikes.

    However, this is not without its problems, as electric modes require lithium and other rare minerals that are not abundant in Europe and increase external dependence.

    battery-free e-bike - Pi-Pop-1

    On the other hand, the lithium extraction process can have a negative impact on the environment.

    Now, French businessman Adrien Lelièvre has devised an innovative and sustainable technology that uses supercapacitors instead of batteries to store energy.

    The electronics-trained inventor’s bike uses supercapacitors instead of lithium electric bike batteries.

    Energy regeneration

    Lelièvre, director of bike manufacturer STEE, explained to the press, “When the ride is easy, the system recharges, and when the bike brakes, the energy returns when needed thanks to engine braking.”

    The Pi-Pop e-bike has no battery, and regeneration is the only way the on-board supercapacitor gets its energy. When the rider steps on level ground, a small amount of energy can be regenerated by using a small portion of the rider’s pedaling force to charge the ultracapacitor.

    battery-free e-bike - Pi-Pop-2

    When traveling downhill, the rider does not need to pedal as hard to maintain speed, and more energy is regenerated at that point than when traveling on flat ground. Applying Pi-Pop brakes restores maximum energy to the ultracapacitor.

    For example, when traveling at 20 km/h on a flat road, the ultracapacitor can be fully charged in 20 to 30 minutes. Using the same principle, energy storage can be effectively regenerated up to about 100W when traveling downhill, even idling.


    “Simply put, supercapacitors work by storing energy electrostatically, i.e. through a slow-moving electric charge.

    Lithium batteries, by contrast, store energy through chemical reactions. In other words, “Supercapacitors can store and release energy very quickly when needed.

    When a person hits the pedals or brakes, they store energy that can be used to help with more difficult maneuvers, such as starting or climbing a mountain.”

    Ultracapacitors have several advantages over batteries, mainly the speed of charging and discharging and their longevity. Ultracapacitors store and release energy ten times faster than batteries.

    battery-free e-bike - Pi-Pop-3

    Rechargeable batteries have an expected cycle life of 500 to 10,000 charges, but ultracapacitors can be recharged millions of times.

    Batteries have a much longer time between charges. However, ultracapacitors recharge by regeneration so quickly that they do not need to be plugged in.

    The French businessman calculated that his ultracapacitor provided cyclists with enough help to withstand a 50-meter elevation gain if previously charged on the plains, making it suitable for about 80% of European cities.

    The first supercapacitors were manufactured in the late 1970s and are now used in solar panels, digital cameras and some hybrid or electric cars to improve their performance.

    battery-free e-bike - Pi-Pop-4

    For Andrian Lelièvre, using this technology on bicycles makes perfect sense. Not least, because no rare raw materials are needed for production, as supercapacitors are made from carbon, conductive polymers, aluminum foil and paper pulp, for which recycling processes already exist.

    Another advantage is that, unlike conventional electric bikes, there is no need to wait for the bike to recharge. Another comparative advantage, the company says, is that ultracapacitors have a lifespan of 10 to 15 years, compared to 5 or 6 years for lithium batteries.

    Reliability of Pi-Pop

    Set in Orleans, the birthplace of its founder, the Pi-Pop weighs 20 kilograms and is in its third generation.

    The local company currently produces 100 bikes a month and employs 25 people. But the plan is ambitious: by 2024, production should jump to 1,000 bikes a month.

    In 2025, STEE will target the European market. This is in line with Brussels’ plans to make 2024 the “Year of the Bike”.

    According to Eurostat, the EU imports 1.2 million e-bikes and 5.2 million conventional bikes, which is five times the amount exported.

    Portugal is the largest producer of bicycles on the European market, producing 2.7 million bicycles in 2022.

    Interestingly, however, it has the lowest investment in cycling networks per capita of any EU country.

    battery-free e-bike - Pi-Pop-5

    By 2021, Portugal will have invested around 30 cents per inhabitant, while some of the most advanced countries have invested tens or hundreds of euros in two-wheeled mobility.

    The Pi-Pop meets the European Class I e-bike standard, which means a top speed limit of 25 KM/H with pedal assist only.The Pi-Pop has no twist or thumb throttle, so you need to pedal for power assist.

    The bike’s Aikema motor and regenerator are rated at 250W(250W e-bike) and 45Nm torque.This may not seem like a lot of power, but given the bike’s approximate weight of 48 pounds and lower US-standard top speed, it’s more than appropriate.

    The Pi-Pop can only be purchased at the company’s factory in Olivet-sur-Loire, France, for €2,450, or about $2,600.

    Hi, I'm an experienced writer about mechanic and an expert on bike and e-bike tech who appreciates practical, beautifully-engineered things. And of course, I love cycling.
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    SAMEBIKE electric bike blog, where you will find all articles about cycling tips, as well as some reviews and newsletters about e-bikes.



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