Greetings,
Being unable to find a datasheet, all I have are some guesses.
I ran into the same kind of problem when taking apart some older Dell battery packs that used TI controllers. TI had made them custom for Dell and data was not available. I got lucky on one of them in that a former tech posted diagnostics data;All of the others I ended up just salvaging the cells.
Now the chip, if I had to guess, it has some type of built in security protocol. The problem is that all we really know is the I2C address, and not much more.

To get any further your really going to have to have it in circuit and put a logic analyzer on it.
If you get real lucky, someone from the boards might know how to unlock it.
GB