interestingly "accu" in french is also used, but only for rechargeable batteries.

Is that official? In spanish, decades ago, the word for battery was "Pila"

"Pila" is a heap of countable physical units, either stacked or disordered. But pila is commonly a fixture for liquids, like septic tank is pila séptica

And batteries were mostly lead-acid. Hence, a pile for/of acid.

I was curious and tried to find out what word Volta used when publishing his discovery, and it looks like he just used "batterie" in his letter (written in French) to the Royal Society: https://royalsocietypublishing.org/doi/10.1098/rstl.1800.001...

I was unable to find out who coined "Voltaic pile" after a few minutes of Googling.