To release the battery holder, simply use your fingernail or a small standard screwdriver and insert into the slot on the holder and press away from the hole.  This will release the spring action and the holder will come out.  See image.

There were 2 versions of the TEBC-(B series), one that used the 2-Spark ignition S16157Y and the newer version that used the battery pack S16272.

w/ Screw x2 S14156, 6-32 X 3/8, PH, Truss, S/S

WARNING

Each, sold separately.