* Major problem for fuel-cell cars is lack of infrastructure
* Daimler-led group to invest in German filling stations
* Group wants about 400 hydrogen pumps by 2023, up from 15
FRANKFURT, Sept 30 (Reuters) - Daimler and five oil and industrial gas companies will invest about 350 million euros ($500 million) on a network of hydrogen filling stations for fuel-cell electric vehicles (FCEVs) in Germany over the next 10 years, they said on Monday.
Fuel-cell cars are seen by many in the industry as the best long-term solution to lowering carbon emissions from road transport, but a major problem - apart from a high price tag - is the lack of a refuelling infrastructure.
"By 2023 there should be more hydrogen filling stations than conventional ones on the autobahn (highway) today," Daimler research and development chief Thomas Weber said in a statement.
The initiative includes petrochemical groups OMV, Shell and Total as well as industrial gases producers Air Liquide and Linde.
The group - dubbed "H2 Mobility" - is aiming to have about 400 hydrogen filling stations in Germany by 2023, the first 100 of which will be working with the next four years. Germany has about 15 such stations now.
Once the scheme is complete, every 90 km (56 miles) of German motorway will offer a hydrogen station, the group said.
Fuel-cell cars chemically convert hydrogen to electricity to power the vehicle, emitting only water vapour as a waste product in the process.
Unlike battery-powered electric cars that have a range often limited to about 100 km and need hours to recharge, FCEVs can refuel within minutes and can travel on one tank distances similar to those of a conventional combustion engine car.
Linde and Daimler were already jointly aiming to invest tens of millions of euros to more than double the number of hydrogen filling stations to 20 by 2015.
The FCEV market is in its infancy, with most cars offered through leasing deals, often as part of corporate fleets, with monthly instalments that industry experts say are often subsidised. FCEVs cost at least 100,000 euros.
Daimler is a leader in FCEVs and said this year that it, Ford and Nissan would within five years launch FCEVs costing not much more than a diesel-hybrid. Mercedes E 300 BlueTEC diesel-hybrids sell in Germany from 52,450 euros.
Daimler has about 200 Mercedes B-Class F-Cells on the road.