Physically the same model batteries have been used on several generations of the ThinkPads. The actual change was from the 55+/55++ battery generation to the 70+/70++ battery generation with the 2012 laptops.
Per a Lenovo staff member in their forums [1],
"The machine will boot (with a warning message displayed by BIOS and by Power Manager), and it will even discharge the unauthenticated battery. The issue is that the machine will not charge the unauthenticated battery. With many of the new systems supporting RapidCharge where you can get to 80% charge in 30 minutes, it is just too dangerous to try to charge someone's aftermarket ebay battery."
" With many of the new systems supporting RapidCharge where you can get to 80% charge in 30 minutes, it is just too dangerous to try to charge someone's aftermarket eBay battery."
I have to agree with that. Search "hoverboard fire". That's what it looks like without all the usual safety devices. Most of the safety devices are in the battery pack.[1] The track record for cheap off-brand battery packs is not good. There are supposed to be seven safety devices,[2] most of which are in the battery pack. A laptop battery without those is a bomb.
Overcharging a lithum-ion battery will cause it to go into thermal runaway and catch fire. The sensors and logic for detecting when to stop charging are mostly in the battery pack. I don't blame Lenovo for being unwilling to charge strange battery packs.
Underwriters Laboratories is, as of this week, offering safety testing and certification for hoverboards.[4] Any previous UL sticker on a hoverboard is fake. UL insists that the battery and charger must be tested and certified together. There's no standard for charger/battery interaction for hoverboards yet. This matters; it's not standardized which side is responsible for which parts of the protection.
Per a Lenovo staff member in their forums [1], "The machine will boot (with a warning message displayed by BIOS and by Power Manager), and it will even discharge the unauthenticated battery. The issue is that the machine will not charge the unauthenticated battery. With many of the new systems supporting RapidCharge where you can get to 80% charge in 30 minutes, it is just too dangerous to try to charge someone's aftermarket ebay battery."
[1] https://forums.lenovo.com/t5/ThinkPad-P-and-W-Series-Mobile/...