Could EV battery health certificates convince more drivers to buy a used EV?

Daily Mail​

24-04-2025

An electric car brand has this week taken radical steps to inspire confidence in the used EV market.
Polestar, which is part of the Chinese Geely Group and a sister brand to Volvo, confirmed its '2' saloons will now be sold with their own 'battery state of health certificates'.
These will certify the condition of the battery and the useable capacity still remaining.
The longevity of battery life remains a major - if not the biggest - hurdle for second-hand car buyers who fear getting stung with a massive bill of up to £30,000 to replace a battery that's been worn out by a previous owner.
That's despite various reports suggesting that EV battery capacity degrades far slower than many people anticipate. In fact, they are claimed to outlast the rest of the car's parts.
Polestar's UK boss said the certificates will give Britons 'transparency' and 'peace of mind' when purchasing second-hand electric cars, which continue to fall in value. But would it be enough to convince you to pick up a used EV bargain?
Auto Trader, the nation's largest used car platform said electric car prices are continuing to decline as the supply of second-hand models isn't being matched by demand.
This is the result of ongoing public concerns regarding the ownership of EVs in general - such as a lack of charging infrastructure, high public charging costs and range anxiety - as well as fears around battery life.
Its latest Retail Price Index report shows used EV availability surged by 54.7 per cent year-on-year in March, largely due to ex-lease vehicles entering the market.
However, this outpaced EV demand growth of 35.9 per cent year-on-year.
'The imbalance between supply and demand is putting downward pressure on used EV prices,' it said.
As such, the average advertised price of an EV listed in March was £25,190, which is 1.6 per cent less than it was in February.
In contrast, prices for petrol and diesel models remained relatively flat, rising by 0.1 and 0.8 per cent respectively from February to March.
In the face of these falling EV values, Polestar said it hopes its certificates will 'gives customers peace of mind that their battery is in peak health and reassurance that many more miles of hassle-free motoring is ahead of them.'
It comes almost two years ahead of new rules that will require all EVs to have a 'battery passport'.
This will not prove the origins of the raw material the battery contains, how much of the content is recycled and their lifecycle carbon footprint, including production and transportation.
From 2027, any new EV sold in the EU will require one - but Volvo last year introduced the world's first battery passport for its flagship EX90 SUV.
Matt Galvin, managing director at Polestar UK, said: 'Where customers may have been apprehensive about a five-year-old Polestar 2 and its battery condition, once again Polestar is giving car buyers transparency and providing peace of mind in the same way we do with our climate impact.'
And in another desperate bid to stir up interest in its second-hand EVs, until the end of the month (30 April), it is offering customers who finance a used Polestar via a franchised dealer a low interest rate and a free Zaptec home charger worth £495.
How much does it cost to replace an EV's battery?
UK-based automotive risk intelligence company Thatcham Research has previously suggested a replacement battery for a 'premium' electric car would cost around £29,500.
For 'budget-friendly' EVs, it estimates the average cost of battery replacement to be £14,200 - that's almost the same as a brand new Dacia Sandero (£14,715).
'EV batteries should last for 20 years'
Given the infancy of EVs, there are still no definitive tests to show how long the batteries will last.
However, a report published last year attempted to quash fears that batteries will run out within a matter of years, suggesting those powered new EVs today should be good for 20 years or longer.
In fact, the investigation said batteries show slower signs of degradation than components used in internal combustion engine (ICE) cars.
The bold claims were made by Geotab - a leading firm in fleet and business telematics, which involves tracking vehicles and connecting them to the internet.
The company says it has carried out analysis of the battery health of almost 5,000 fleet and private EVs, using 1.5 million days of telematics data to explore how the latest battery technology holds up to the rigours of daily use.
The data suggested that EV batteries in current models degrade, on average, by 1.8 per cent annually.
When it carried out the same study back in 2019, it found that the efficiency of batteries was declining at a rate of 2.3 per cent per year on average, suggesting advances have been made in the last five years to extend the lifespan of the technology.
What is battery degradation - and should it stop you switching to an EV?
Battery degradation is a natural process that permanently reduces the amount of energy a battery can store or the amount of power it can deliver.
The batteries in EVs can generally deliver more power than the powertrain components can handle.
As a result, power degradation is rarely observable in EVs and only the loss of the battery's ability to store energy matters.
An EV battery's condition is called its state of health (SOH).
Batteries start their life with 100 per cent SOH and over time they deteriorate.
For example, a 60kWh battery with 90 per cent SOH would effectively perform like a 54kWh battery.
The report went on to say that EV batteries now 'generally degrade more slowly than internal combustion engine drivetrain components'.
David Savage, vice president for the UK and Ireland at Geotab, added: 'With these higher levels of sustained health, batteries in the latest EV models will comfortably outlast the usable life of the vehicle and will likely not need to be replaced.
'However, we still see battery reliability being used as a stick to beat EVs with.
'Hopefully, data like ours can finally put these myths to bed.'
The report says an average 1.8 per cent decline in battery health is 'unlikely to have a significant impact on most driver's daily vehicle needs'.
It adds that this degradation should decline in the future with the arrival of new EV models and further advances in batteries, such as solid-state battery tech.
'People should feel confident that many current EVs are suitable and cost-effective to replace a range of light, medium and heavy-duty ICE vehicles,' David went on.