PARIS - Taiwanese battery maker ProLogium Technology Co plans to gradually ramp up its 5.2 billion euro ($5.7 billion) factory in France as it looks to boost efficiency and responds to a slowdown in EV sales, its CEO told Reuters.

Privately-held ProLogium, in which Mercedes-Benz is an investor, is counting on its next-generation technology to be attractive to automakers even amid a market slowdown, with sales of new EV cars in the EU down 12% in May.

"We don't want to expand too quickly," CEO Vincent Yang said in an interview at the World Materials Forum in Paris. "It will depend on the automakers."

Several battery makers in Europe have curbed expansion plans as consumers wait for more affordable models. Sweden's Northvolt for instance last week launched a strategic review.

ProLogium's gigafactory, planned to be built in Dunkirk, northern France, and backed by French government investment, is still on track to start construction late this year or early in 2025 and to start production in 2027, Yang added.

The final capacity of the Dunkirk plant is due to be 48 gigawatt hours GWh, but it will initially start at 2-4 GWh and likely increase to 8-16 GWh by 2030, he said.

Besides assessing orders from automakers, ProLogium will boost the plant's efficiency, with four successive versions of the battery to be rolled out by 2032, when full capacity is due to be hit, he said.

ProLogium believes its new technology using a ceramic separator, silicon anode and nickel manganese cobalt (NMC) cathode will be in demand due to its short charging times and high density.

Yang said a five-minute charge of its battery would provide a driving range of 300 km, compared with 30 minutes for a similar distance for a typical lithium iron phosphate (LFP) battery.

ProLogium's new battery is a partially solid-state design utilising some of the benefits of the solid-state technology that has been held up as a game changer for EVs, but has been fraught with technical issues.

"We could do both pure solid-state and semi-solid state, but there are cost issues," Yang said.

The ProLogium battery is more expensive than an LFP battery, costing about $170 per kilowatt hour (kWh) versus $100-$115 for LFP, but the pack price for a vehicle is only slightly more because the battery is smaller and lighter, he added.

  - Reuters