I have a Travelscoot also and have taken it all over the world. This is what is on the FAA site so you are good.
Electric wheelchair, mobility scooter
In cases when the batteries are adequately protected, it is preferable that they remain installed in the mobility aid; however, there may be situations when that is not possible or safe to do so and in these cases the batteries must be removed. This description is for a wheelchair or mobility device that does not have a protective housing for its lithium ion battery, i.e., the mobility aid does not provide adequate protection to the battery. Lithium ion battery size is limited to 300 watt hours (Wh). One spare battery not exceeding 300 Wh or two spare batteries not exceeding 160 Wh each may be carried in carry-on baggage.