I get that most people haven't heard of rechargeable battery packs for laptops.
But incredulity is not falsification, and what I had was a laptop with a rechargeable alkaline battery pack.
It is practically impossible to prove a negative. But you could easily prove the existence of such a laptop by finding documentation of it: an old ad or datasheet or review or something. Even without knowing the model name, you would find some sort of evidence that somebody once made such a thing.*
You are the one making the extraordinary claim, so the onus is on
you to prove it.
Meanwhile, the characteristics of rechargeable alkalines (low cycle count, poor high-current performance) make them unsuited to laptops, making it exceedingly unlikely that anyone would select them for that application.
*I did search (Google, archive.org, Google patents) and came up with absolutely nothing supporting the existence of such a laptop. I did, however, find evidence supporting its nonexistence. The company that developed rechargeable alkalines, Battery Technologies Inc of Canada (founded 1986), had the following item in their
FAQ on their website in April 2003:
(10) Are RAM cells available for camcorders, video cameras, cellular phones, etc?
All these so called OEM (original equipment manufacturing) applications use battery packs. Currently NiCad and NiMeHydride packs are available for these applications, and are very unpopular due to problems with the “memory effect” under actual use conditions. BTI's R&D lab is working on the development of battery packs for the OEM market.
If they had already produced laptop batteries, they would clearly have said so.
Regardless, they never got the chance to make any, because April 2003 is also the same month the company
went out of business.
(The persons involved in BTI also
moved on to other companies in 2003.)
Anything later than this is too late for your timeline of having disposed of it 20 years ago, so BTI was responsible for the entire rechargeable alkaline technology during the laptop era through 2003. (Prior rechargeable alkalines were only on the market
briefly in the early 70s, much too early for any laptops.)
So I’d call your claim “busted” absent actual proof of its existence. Whatever your laptop used, it wasn’t rechargeable alkaline.