That wouldnt help with the regenerative breaking aspect though.
Have you looked in to using LiFePO4 batteries? IDK how they stack up to LiPo in terms of discharge and recharge rates but I do know that this is a really common thing for the bass heads to use in their redonkulous 25000W+ car...
The advertised C ratings are complete lies. About the highest TRUE C rating you can find on a Lipo is about 40C discharge or so on the best of LiPos. If you want your batteries to last I wouldnt charge them over 2 or 3 C and most manufacturers advertise a limit of about 5C charge rate.
Try...