[Rogerpaine]

I thought I was making zinc chloride from HCL and a single use battery case for the zinc source but the reaction wasn't as expected. I discovered that I'd used an alkaline battery case which isn't zinc. The battery case dissolved slowly leaving something that looks like thin plastic film floating in the jar. The reaction has produced a deep violet liquid. My web searches suggest the battery case is nickel plated steel but it seemed too soft and flexible for steel. Can anyone tell me what it is?
thanks

[AWK]

My guess - this was HNO₃ instead of HCl.

[Enthalpy]

Look at the battery model's + electrode: if it's the same part as the casing, without insulation, it implies that the alkaline battery model has its zinc electrode at the centre, the MnO₂ around it, and the outer metal is only a casing, as in
https://en.wikipedia.org/wiki/Alkaline_battery third illustration
Steel with some noble protective layer seems a good choice for the casing.

[Intanjir]

Modern pennies are like 99% zinc underneath their copper cladding.
Manganese makes for some colorful solutions.