Here is the link that segrick sent to me.
http://www.regulations.gov/#!documen...2009-0095-0300
172.102 Special Provisions
- must be consigned under the entries “Lithium metal batteries contained in equipment” or “Lithium metal batteries packed with equipment” or “Lithium ion batteries contained in equipment” or “Lithium ion batteries packed with equipment” as appropriate.
The above specifically applies to those items being shipped not checked at the gate. If you look under IATA regulations (governing body for Hazmat air shipments) you will find that these would still be fully regulated hazmat and must be packaged and shipped as UN3480 if the batteries are sent on their own or UN3481 if they are shipped installed on equipment. By either method they are "Forbidden aboard passenger aircraft". IF you look in the CFR49 which is PHMSA's book you will find these are again "Forbidden aboard passenger aircraft".
Within the link if you search the special provision A54 you will find: Irrespective of the quantity limits in Column 9B of the § 172.101 table, a lithium battery, including a lithium battery packed with, or contained in, equipment that otherwise meets the applicable requirements of § 173.185, may have a mass exceeding 35 kg if approved by the Associate Administrator prior to shipment.
Column 9B is applicable to Cargo Aircraft Only shipments and is not a provision that applies to passenger aircraft.
Sorry to seemingly keep pushing back on this but I am not seeing any regulations which accomplish legal air travel aboard passenger planes with lithium batteries on a Segway. The one large hurdle is that Segway does not condone or endorse the Segway to be used as a mobility device. Hence, I think without their endorsement you would still be sitting is somewhat of a grey area since the Segway could then be argued not to applicable to rules developed for that use.