I've been running the LiHV Intellect batteries for over a year in my 2WD mod buggy. Despite regular use under relatively high stress on high grip tracks they have shown no sign of swelling. Previous batteries over the last few years have always shown some swell after a year or so.
So I would say they have improved, I don't know whether this is down to LiHV, graphene or something else.
http://www.racing-cars.com/pp/Manufa...2S3600HV2.html