can two of these protection boards be used?

is it possible to connect two of these together somehow if I have 2 lithium ion batteries in series?? Also, the data sheet is a little confusing...is the board diameter 8.65mm (R=round?) or is that the radius? THANKS!

It has a radius of 8.65mm's and a depth of 1.72mms
So it's 17mm's across, and 1.72mms thick.

Does not look like it would work in series.