The leasing scheme provided by Renault for the Zoe was an attempt to reduce the initial cost of electric vehicles by treating the battery as separate from the rest of the vehicle. While the car itself could be bought on hire purchase, if the agreement for the battery is on a lease then this is effectively a rental price you are paying on a monthly basis - it is not a hire purchase agreement, so it does not matter how many months you pay the lease fee, you will still not own the battery. The £2,000 is the purchase price for the battery to own it outright, and this figure is independent from how many monthly lease payments you have made. Your options are to pay to own the battery outright, pay to have the battery removed and returned to Renault - although of course this will require you to replace it with another battery if you wish to continue using the car - or you can sell the car, but the new owner would need to take over the lease.