I've not found any reference anywhere to a vehicle insurer refusing to insure vehicles with lithium-ion batteries. It is, however, a hot topic (pun intended) for product liability insurers and cargo transport insurers. The manufacturers of batteries or the products containing them have primary liability for failures, so their insurers are keenly interested in the risks. Cargo transporters and their insurers worry about hidden risks when they unknowingly transport items that have Lithium-ion batteries, whether it is a single electronic gadget in somebody's luggage or a shipping container full of them.
I think, though, that it is only a matter of time before some RV burns as a result of Lithium battery failure and safety questions arise. RVs are designed to handle lead-acid technology and have no built-in safeguards for lithium. The lithium batteries packaged as 12v lead-acid replacements do have internal BPS, but the battery storage area and battery charging systems do not. Further, deep-cycling is one of the stressful uses that can lead to lithium cell failures, but few RV owners regularly monitor battery discharge rates or watch for signs of imminent failure. How often do we see or hear of lead-acid batteries failing due to neglect or system problems caused by corrosion or bad connections? There will be a great hue & cry when the first RV fire involving a lithium battery occurs.
