What Is Battery-as-a-Service? A Plain-Language Guide

Imagine using a battery without ever owning it: paying for access instead, the way you might pay for a phone plan rather than buying every component inside it. That is the basic idea behind Battery-as-a-Service, or BaaS. It already exists in electric vehicles, and it is starting to extend well beyond them, into portable power, industrial equipment and stationary energy storage.

This article explains what battery as a service actually means, walks through a concrete example, and looks honestly at both the promise and the open questions, including why CIRCUBATT is testing its own version of the model as part of building a more circular battery value chain.

Battery-as-a-Service, in plain terms

In a standard purchase, you buy the battery along with the device or vehicle it powers, and you carry responsibility for it for the rest of its life. BaaS separates the battery from the product instead. You pay for access to a working battery, usually through one of two arrangements:

• Leasing or subscription, where you pay a regular fee to use a battery over time, while the provider keeps ownership and handles warranty and maintenance.
• Battery swapping, where you exchange a depleted battery for a fully charged one at a swap station in minutes, cutting out the wait to recharge.

A concrete example: a logistics company needs temporary power for equipment at a construction site. Instead of buying a battery system outright, it rents a tested, health-assessed battery for six months. The provider monitors its condition, maintains it, replaces it if performance drops, and recovers it at the end of the rental.

This is already a real, growing market for electric vehicles specifically. Companies such as NIO, Renault Group and BYD offer versions of battery leasing or swapping today, and broader industry interest in similar models keeps growing, including among established automotive manufacturers. Programme maturity still varies a lot, though, so readers shouldn’t assume every one of them is a finished, market-ready product. The direction of travel extends beyond cars either way: the same logic applies to portable power tools, industrial equipment and stationary storage.

What “second-life” actually means

An electric vehicle usually retires its battery because the battery can no longer deliver enough driving range, not because it has stopped working. That battery can often still hold and deliver meaningful charge, just at a lower level than a new one. That makes it well suited to applications with lower performance demands, such as stationary energy storage, where the priority is holding capacity rather than powering a fast-accelerating vehicle. This is what “second-life” means: a battery moving from a demanding first job into a less demanding second one, not a battery sold as new and not one thrown away.

Why this matters for the circular economy, and where it doesn’t automatically deliver

When a provider keeps ownership of the battery, it gains a direct financial reason to make that battery last and to recover it responsibly at the end of its use, rather than let it end up as waste. That gives BaaS a genuine structural advantage over a model where the customer owns the battery outright and has no similar incentive.

It isn’t an automatic outcome, though. Retained ownership can create stronger incentives for maintenance, reuse and recovery, provided the company actually builds its contracts, product design and reverse logistics to support that outcome. A provider optimising purely for low-cost replacement, or managing recovered assets poorly, won’t deliver those circular benefits just because it happens to own the battery.

This is also why BaaS connects to the broader “Reduce, Reuse, Repair, Remanufacture, Recycle” hierarchy that underpins circular battery value chains. A service model only supports circularity if manufacturers design the battery to be durable and repairable, and if the systems around it can actually recover and redirect it, not simply because ownership changed hands.

What Battery-as-a-Service does not mean

To avoid some common misunderstandings:

• It does not necessarily mean battery swapping. Leasing, subscription and rental models exist without any physical swap station.
• It does not mean the battery is free. You still pay, usually on a recurring basis, for guaranteed access and upkeep.
• It does not automatically make battery use circular. That depends on how the service, contracts and logistics are designed.
• It does not mean every used battery is automatically safe or suitable for reuse. Someone has to verify that, every time.

CIRCUBATT’s own take on BaaS

Most BaaS models on the market today use new batteries. CIRCUBATT is exploring something more specific: business models based on second-life batteries. The project is examining several service types, summarised in the table below.

How AI and data support these services

Reliable versions of these services depend on the same underlying ingredient: accurate data on a battery’s state of health, state of charge, usage history and remaining useful life. Data-as-a-Service aims to supply exactly that data, and any AI-based matching behind a personalised plan works from it directly, matching a battery’s real condition to a use case it can actually handle.

Looking further ahead: peer-to-peer exchange

Longer term, the project is also examining decentralised exchange models, where tested batteries that have finished their first application, not their working life entirely, could move to verified second-life users through traceable platforms. This differs from an informal swap between individuals: it depends on testing, traceability and safety verification at every transfer.

None of this is a finished product yet. It’s exploratory research: CIRCUBATT is testing whether these business models hold up economically, socially and operationally before anyone builds a market around them.

What has to be solved first

Second-life BaaS is genuinely harder to run than a service built on new batteries, for reasons worth stating upfront:

• Batteries arrive with varying chemistry, format and degradation, which complicates standardisation.
• Historical usage data is often incomplete, which makes assessing condition harder.
• Every battery needs testing and a state-of-health check before reuse.
• The sector needs clear rules on safety certification and liability.
• Transport and storage of used batteries bring their own requirements.
• Warranty responsibility and reverse logistics both need workable, agreed structures.
• Predicting a battery’s residual value, and gauging real customer demand, both carry uncertainty.

None of this rules out the model. These are exactly the questions a research project like CIRCUBATT exists to test, rather than assume.

What still needs to be validated

CIRCUBATT’s work on BaaS aims to answer these questions, not assume the answers:

• Whether recovered batteries are technically sound and safe for a given second application.
• Whether real customer demand exists at a workable price point.
• How to structure pricing and contracts so they share risk fairly.
• Whether logistics and maintenance costs make the model viable.
• Whether the environmental benefit actually holds up against simply not reusing the battery.
• How to govern and track battery data across different users.
• What regulatory requirements apply as the model scales.

The honest bottom line

BaaS isn’t automatically cheaper or more sustainable than owning a battery outright. Its success depends on accurate battery-health assessment, safe and standardised systems, efficient collection and redistribution, clear responsibility when something fails, and enough customer demand to cover the cost of monitoring, maintenance and logistics. These are precisely the questions CIRCUBATT is testing, not assuming.

Frequently asked questions

Is BaaS cheaper overall, or only cheaper upfront?
Usually cheaper upfront, since you skip paying for the battery outright. Whether it’s cheaper over the full term depends on the fee structure and how long you use the service, so you need to compare it case by case rather than assume an answer.

What happens if the battery fails or underperforms?
Under a BaaS contract, the provider generally takes responsibility for replacement or repair, since they retain ownership. The exact terms, including any guaranteed minimum performance, depend on the specific contract.

Am I responsible if I damage the battery?
That depends on the contract’s terms, in the same way a leased vehicle or a rented tool carries its own damage terms. It’s one of the contractual questions CIRCUBATT’s business-model research is examining.

How do you verify a second-life battery’s safety?
Through testing and a state-of-health check before the battery enters a new service, covering things like remaining capacity, degradation and safety indicators. This step is non-negotiable in any responsible second-life model.

Can you use the same battery across different products?
Potentially, if testing confirms it matches the performance needs of the new application. This is part of what “personalised battery plans” and Data-as-a-Service are meant to determine.

What happens to the battery after its second life ends?
The intended pathway is recovery for recycling, so materials can re-enter the value chain rather than becoming waste. That end-of-life recovery step is itself part of what a well-designed BaaS contract needs to plan for.

CIRCUBATT’s work on BaaS forms part of a wider set of tools the project is developing across the battery lifecycle, from smarter recycling processes to AI-based lifecycle management. You can explore the full scope of that work on our Work Packages page.

Want to understand the next piece of circular battery vocabulary? Follow CIRCUBATT on LinkedIn — we publish a new plain-language explainer every few weeks.