Hi Hampus. As far as I can tell, the cells drive the LED because if the cells are discharged, as they were when I inherited the torch, it simply doesn’t work no matter how much you shake the generator. It looks like it was made like that. I could understand it if the cells were rechargeable, but they’re standard coin cells.
Here’s another old-ish torch that I bought my wife in around 1980. It’s a Duracell ‘Durabeam’ which works pretty well, once I cleared away the corrosion left by the original Duracell batteries...
Phil