you may run into trademark laws if your code answers 'you are connected to a Bosch xxx battery' when the customer switches on.
Take my word for it guys there is absolutely nothing that cannot be hacked. Mobile phone technicians developed locked boot loaders on cell phones to prevent hackers using their own firmware, enthusiasts like myself overcame that years ago. Then manufactures added things like Knox security to flag up if a phone had been flashed with a different firmware, that's been circumnavigated too.
But it's like I said there's no will or interest in electronic cycle propulsion systems that would grab the attention of firmware hackers to any great extent, a little but not much.
As far as messages appearing on a LCD telling you that you can't do this or that with your own piece of equipment, most of that nonsense contravenes EU/UK law. It's been tried on printer cartridges, camera batteries, mobile phone batteries, I could go on and on.