Battery health transparency key to EV consumer confidence

Real-time battery health information will be a step-change for owners of EVs and buyers of second-hand battery-electric vehicles, according to Polestar cell specialist and researcher David Maibach.

Maibach spoke with carsales in an exclusive interview at Polestar HQ in Gothenburg, Sweden last week.

Commenting on consumer concerns about batteries, which surfaced in carsales’ most recent tranche of EV intender research, the Polestar exec was guarded on his claims regarding real-world battery longevity, but pointed to the long warranties Polestar and other EV brands were already offering.

Maibach said initial results across the Polestar 2 fleet are positive, with lower than expected battery degradation rates. The performance of home AC-charged Polestar 2 batteries is even better, the cell researcher revealed.

“If you mainly charge at home using AC – 22kW or below – it’s very good. If you use more fast-charging – DC charging 150kW or above – you see some variance, but it's actually quite good,” said Maibach.

“And then we can see that there’s some variance depending on where in the world our cars are being used. If you have a car for example in urban Shanghai, they might use more fast-charging because there’s not as much home charging availability.

“Whereas here in Sweden and Norway it’s more home charging. So it [battery health] becomes very much linked to the infrastructure of charging.”

Responding to a question about these lower than expected battery degradation rates versus EV battery warranties, Maibach commented: “I would say that’s [current warranty provisions] quite conservative. They [EV batteries] will most likely perform better than that.”

Polestar currently offers an eight-year, 160,000km warranty for its batteries. Any material defects are covered and if the battery tests at less than 70 per cent of its original capacity within those eight years Polestar will replace the battery free of charge.

Maibach contends that the battery warranties currently offered by EV brands “says quite a lot”.

“Usually we benchmark towards 80 per cent. It [the battery] will still perform very well.

“[But] The better question is what happens once it reaches 80 per cent? If that happens at 200,000km or 300,000 – it doesn't really matter. Eventually it's going to reach 80 per cent.

“Then how do you replace it and do you replace the whole pack or do you basically take it to a workshop and ask them to replace the bad cells?

“Because in a pack you might have 200 batteries, if 2 per cent of them are bad, why would you replace the whole pack? So what we are doing is trying to make it easier for workshops to open up the packs, remove the ones that are bad and replace them…”

Even if consumer pressures are not enough, legislation will require battery health data to be visible in EVs. Maibach agrees that transparency on this is a game-changer for EV ownership and resale values.

“That’s [battery health metering] something that the manufacturers need to have implemented and available within the car. [Right now] It would be very, very hard to take to the workshop and accurately determine the state of health. I would say it’s much more relevant if we [OEMs] develop the system,” he opined.

“Within a few years we’re going to have state of health indicators in every car that’s going to tell you what your car [battery’s] state of health is. You can know and you can predict that ‘OK, maybe now it’s time for a check-up’ and then we can see if there are any faulty cells that should be replaced,” he explained.

“It’s the same as having your ICE car being serviced – where you replace certain key components. They have a lifetime because that’s mechanics. We can’t change that.

“I think that’s a more transparent way of going around it instead of us giving you a blanket answer for the whole fleet,” Maibach stated.

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