This question was posed to all the major manufacturers. You would have thought a straightforward question would elicit a straightforward answer. But somehow Skoda gave a convoluted reply and avoided answering the question, Seat maintains it uses lithium ion batteries which surprised me, VW remained shtum.

 

https://www.honestjohn.co.uk/coronavirus/coronavirus-will-trickle-charging-or-jump-starting-your-cars-battery-invalidate-the-warranty/

4 hours ago, xman said:

Seat maintains it uses lithium ion batteries which surprised me

Whoever at SEAT answered the question doesn't have a clue - yes EVs and hybrids use Lithium Ion batteries (for the propulsion batteries) but ICE and hybrids use Lead acid batteries (for the non-propulsion batteries).