On UX.Stackexchange there was a thread about how to help users distinguish rechargeable batteries
from plain ones. I thought that a sticker printed on "rough" material might help, as it can give both visual and haptic input on the packaging and on the battery itself.
I have combined a symbol that is common for refreshing or updating, the plus and minus signs on the batteries, and made sure that the arrow of the symbol shows upwards and includes the plus sign; this way it gives an almost uplifting feeling when recharging.
I have worked with stickers before and I find them an excellent solution, as they minimise the need to physically hack the product itself when distinguishing variations is needed.