Here's a battery density graph, there are a variety of these out there but give a good approximate comparison of different types. https://media.monolithicpower

Here's a battery density graph, there are a variety of these out there but give a good approximate comparison of different types. https://media.monolithicpower.com/wysiwyg/Educational/BMS_Chapter_1_Fig4-_960_x_709.png https://media.monolithicpower.com/wysiwyg/Educational/BMS_Ch... Lead acid I believe is what was accessable for automotive purposes 100 years ago. Li-ion cells have about 50-60 years of research in them with maybe 30 where they've been able to be used in automotive applications.