You could look into cheaper batteries, as there is no need to use the latest and greatest technology. Supercapacitors might also be an option.
It's all an economic sum, really: when do the higher connection fees and increased demand pricing outweigh battery cost? We are already seeing grid-scale battery storage being used in practice, applying that to a more local use case might not be that unrealistic.
Besides, if the alternative is no charging station, you can probably charge significantly higher fees.
