The batteries used in e-bikes - and in everything from electric cars to our cellphones - have significant problems. Environmental degradation from strip mining, pollution and human rights concerns plague the mining of the materials needed in current designs (and their manufacture). Plus, as production of electric cars ramps up and we develop more utility systems for storing solar and wind power, we are heading towards shortages of these materials.
Lithium can make up close to half of current vehicle batteries and is strip mined causing significant environmental damage[1]. Nickel, cobalt and graphite are also used in many lithium ion battery designs and are linked to serious pollution issues, human rights violations and, at least in the case of nickel, high embodied energy [2, 3, 4]. While the overall impact is arguably better than the fossil fuel industry it is replacing, it is still an issue of concern. Plus as demand for EVs skyrockets, we are facing serious shortages of these materials[5].
We need better recycling programs to reuse these materials at the end of the battery's useful life and better battery designs that use less problematic materials. What we should not do is avoid e-bikes because of battery challenges.
Just as every e-bike trip that replaces a gas car trip dramatically reduces climate change emissions, every e-bike trip that replaces an electric car trip dramatically reduces lithium, cobalt and graphite usage. We evaluated warranted battery consumption by e-bikes and electric cars and found that e-bikes get 30 to 100 times more miles per pound of battery than electric cars.
Just as with climate emissions, the battery use of e-bikes is vanishingly small compared to electric cars. Using e-bikes instead of electric cars whenever possible buys time to develop better battery solutions for electric cars.
For electric cars we used the specs for the 2017 Tesla Model S 75: 1200 pounds of battery warranted for 100,000 miles[6]. The Tesla is one of the most efficient electric cars on the market. Divide the warranted miles (100,000 miles) by the battery weight (1,200 pounds) to get 83 miles per pound of electric car battery.
E-bike battery warranties are usually based on time or cycles instead of miles of range. Various manufacturers indicate an expected decline of battery capacity to 80% at 500 cycles and 60% at 1000 cycles and warrant one of both of those levels of performance[7]. For our e-bike battery life analysis we used the specs of the Bosch 400 Powerpack, a battery found on many e-bikes on the market today.
Miles per charging cycle varies widely depending on conditions - what level of support, weight of ride, bike & cargo, hills, etc. We used the Bosch Range Assistant to bracket the predicted range of miles per charge for the Bosch 400 Powerpack at 24-83 miles[8]. We de-rated these ranges by 80% assuming that users recharge before the battery is absolutely empty. We de-rated the range by another 80% to take the 500 cycle midpoint in battery capacity decline on the way to the warranted 60% as the lifetime average. This results in a de-rated range of 15 to 53 miles per charge.
The Bosch 400 weighs 5.5 pound[8]. Divide the expected miles in the warranted charging cycles (15 to 53) by the battery weight (5.5 pounds) to get 2793 to 9658 miles per pound of e-bike battery.
This actually works out to 34 to 116 times more miles per pound than the Tesla, but we round it down to 30 to 100 times more miles per pound than the Tesla to be conservative.
This is a conservative estimate as e-bike battery manufacturers are innovating to pack more energy per pound into their batteries. The Bosch 500 has 25% more capacity than the 400 for only 4% more weight (0.1 kilogram or 0.2 pound) [9].
The electric vehicle battery recycling industry is building up capacity fast - maybe even faster than the supply of used batteries[10]. The U.S. e-bike industry has collaborated to create the Call2Recycle Electric Bike Battery Recycling Program to safely and responsibly collect batteries for recycling at the end of their life to keep them out of the landfill and reclaim the valuable materials inside. [11]
Ready to buy an ebike? Find brands that are participating in the recycling program.
Have an ebike battery to recycle? Find a drop off location.
Ebike retailer? Sign up so you can recycle batteries
More studies on e-bikes - how and why people ride them, their impacts and the effectiveness of incentive programs - can be found at the ClimateAction Center's E-bike Studies page.