Lithium batteries in e-bikes

Electric bikes are often celebrated as one of the most hopeful tools in the fight against climate change. They’re quiet, efficient, and capable of replacing countless short car journeys.

For many riders, e-bikes open up cycling to longer distances, steeper hills, and older or less able bodies. But beneath that clean, green image sits a small yet complex component that deserves closer attention: the lithium-ion battery.

While e-bikes are undeniably part of a lower-carbon future, their batteries carry environmental and social costs that are easy to overlook — and increasingly important to understand as e-bike use continues to grow.

A small battery with a big footprint

Compared to electric cars, e-bike batteries are tiny. Most fall between 250 and 1,000 watt-hours, roughly 0.25–1 kWh. Yet even at this scale, battery production is energy-intensive.

Life-cycle assessment (LCA) studies estimate that manufacturing lithium-ion batteries can produce anywhere from 40 to over 200 kilograms of CO₂ equivalent per kilowatt-hour, depending on where and how they’re made.

Some broader EV studies report even wider ranges due to differences in methodology and supply chains.

Put simply, a typical 500 Wh e-bike battery may embody around 40–100 kg of CO₂ before it ever reaches the rider.

That’s still far lower than the footprint of a car battery but it’s far from zero.

The good news is that once an e-bike is on the road (or trail), emissions drop dramatically.

Charging an e-bike uses very little electricity, and multiple transport studies show that e-bikes emit only single-digit to low-tens of grams of CO₂ per kilometre over their lifetime.

Compared to a petrol car — often exceeding 200 g CO₂ per kilometre — the savings are substantial, especially when e-bikes replace car journeys rather than walking or conventional cycling.

Where the materials come from

Lithium-ion batteries rely on a mix of materials: lithium, cobalt, nickel, manganese, copper, and aluminium. Extracting these materials is where many of the most serious environmental and social issues arise.

Lithium extraction, particularly from brine deposits in arid regions, can place heavy pressure on water supplies and local ecosystems.

Hard-rock mining, meanwhile, brings habitat destruction, energy use, and waste rock.

As global demand for batteries increases, ore quality often declines, meaning more land, water, and energy are required for the same amount of material.

Cobalt presents an additional ethical challenge. A significant share of the world’s cobalt comes from the Democratic Republic of Congo, where mining has been linked to unsafe working conditions, child labour, and community displacement.

While many manufacturers are working to reduce cobalt content or improve supply-chain transparency, these issues remain deeply embedded in global battery production.

Manufacturing: clean energy, dirty chemistry

Battery manufacturing itself carries environmental risks beyond carbon emissions.

The process involves complex chemical treatments, solvents, and, in some cases, persistent synthetic compounds such as PFAS-related chemicals.

These substances, sometimes called “forever chemicals,” do not easily break down in the environment and have been linked to long-term ecological and health concerns.

Investigations near battery manufacturing sites and waste facilities have raised concerns about soil and water contamination when these materials are poorly managed. While regulations are improving in some regions, global standards remain inconsistent.

The recycling problem no one sees

Perhaps the weakest link in the e-bike battery story is what happens at the end of its life.

Globally, only a small fraction of lithium-ion batteries are currently recycled, with some estimates placing recycling rates in the single digits. Small-format batteries — like those used in e-bikes — are particularly difficult to collect and process because they vary widely in design and chemistry.

As e-bikes, e-scooters, and other light electric vehicles multiply, researchers warn of millions of tonnes of battery waste by 2040 if recycling systems don’t scale up quickly.

Without proper infrastructure, batteries risk ending up in landfills, where toxic components can leak into soil and water — or being improperly dismantled, creating safety and pollution risks.

Do e-bikes still make sense environmentally?

Despite these concerns, the overall picture remains encouraging.

Most life-cycle studies conclude that e-bikes deliver clear net environmental benefits, particularly when they replace car trips.

The emissions associated with battery production are typically “paid back” relatively quickly through low-carbon travel. Over years of regular use, an e-bike can prevent hundreds or even thousands of kilograms of CO₂ compared to car use.

But the benefits are not automatic. If e-bikes replace walking, public transport, or traditional cycling, the climate gains shrink.

The real environmental win comes when e-bikes are treated as car alternatives, not novelty gadgets.

Making e-bikes genuinely sustainable

If e-bikes are to remain a positive force for the environment, several changes are crucial:

• Longer-lasting batteries: extending battery lifespan by even a year or two dramatically reduces emissions per kilometre.

• Repairable and modular designs: replacing cells or modules instead of entire packs reduces waste.

• Clear take-back and recycling schemes: riders should know exactly where their battery will go at end of life.

• Responsible sourcing: stronger oversight of mining practices and supply chains is essential to reduce human and ecological harm.

• Better policy: extended producer responsibility and investment in recycling infrastructure will be key as e-bike use expands.

  
  

The bottom line

E-bikes are not perfect — but few transport solutions are.

Lithium-ion batteries come with real environmental and ethical costs that deserve honest discussion, not greenwashed marketing.

Yet when used thoughtfully, maintained properly, and supported by responsible industry and policy, e-bikes remain one of the most efficient and climate-friendly ways to move people through towns, cities, and landscapes.

The challenge now is ensuring that the technology evolves in a way that protects not just riders, but the communities and ecosystems that make it possible.