I picked up some used 2.0a batteries on ebay to play with. One seems to be bricked so I didn't mind tearing into it deeper. As M52 already mentioned, the protection must be built into the tools. The main terminals are wired directly off the cells. Also, confirming this 2.0 battery is 14 cells in series.
The heat sink around the cells is some sort of fiber reinforced plastic. It almost looks like there are specks of copper in it too and it's very brittle. (See photo.) I'm skeptical of the claim about this material being phase changing.
The only marking on the cells is: TAB4RXA, followed by a 6 digit # that is different on each cell. This doesn't mean anything to me... any ideas?
The really interesting thing to me about Ego 56 is the 7.5a battery. It's about the right size for many bike applications. Also the 14s voltage is good for a boost on most 36/48v setups while staying under 60v. Some of the tools look pretty awesome too like the mower and a 480cfm blower. The quick charger looks decent too. The battery is expensive, but it's about the same per WH as any other tool battery.
There's also an interesting looking 80v line of tools by Greenworks now, but no high capacity batteries yet.

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